Add -Wconversion to various things in src/app

[bzbarsky-apple]

Problem

We are not using -Wconversion to build things in src/app, so we won't catch problems as we start changing the sizes of things like cluster/endpoint/attribute ids.

Change overview

Add -Wconversion to some of the relevant .gn/.gni files, fix resulting problems.

Testing

Compiled the code on esp32, Mac, nrfconnect.

[github-actions]

Size increase report for "nrfconnect-example-build" from 336533f

File	Section	File	VM
chip-lock.elf	device_handles	-4	-4
chip-lock.elf	text	-12	-12

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-lock.elf and ./pull_artifact/chip-lock.elf:

sections,vmsize,filesize
.debug_info,0,281
.debug_str,0,65
.strtab,0,42
.debug_line,0,36
.symtab,0,32
.debug_frame,0,16
.debug_abbrev,0,15
.debug_aranges,0,8
.debug_ranges,0,8
.shstrtab,0,-2
device_handles,-4,-4
text,-12,-12
.debug_loc,0,-333

[mspang]

auto -> int?

[bzbarsky-apple]

I could do that, but the point is we don't really care what this gets promoted to by C's rules. We just check that it's in-range and then cast it to the type we really want... So I was pretty carefully avoiding using int there.

[mspang]

It's not that we care or don't care. It's that the type is clear and it's "int". It isn't going to change and there aren't any other promotion rules like that. Why obfuscate?

[github-actions]

Size increase report for "esp32-example-build" from 336533f

File	Section	File	VM
chip-all-clusters-app.elf	.flash.rodata	24	24
chip-all-clusters-app.elf	.flash.text	-24	-24

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize
.debug_info,0,122
.debug_ranges,0,104
.debug_str,0,68
.strtab,0,42
.debug_frame,0,24
.flash.rodata,24,24
.symtab,0,16
.debug_aranges,0,8
.shstrtab,0,-2
.flash.text,-24,-24
[Unmapped],0,-24
.debug_abbrev,0,-63
.debug_line,0,-212
.debug_loc,0,-467

Comparing ./master_artifact/chip-pigweed-app.elf and ./pull_artifact/chip-pigweed-app.elf:

sections,vmsize,filesize

[github-actions]

Size increase report for "gn_qpg6100-example-build" from 336533f

File	Section	File	VM
chip-qpg6100-lighting-example.out	.text	-8	-8

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-qpg6100-lighting-example.out and ./pull_artifact/chip-qpg6100-lighting-example.out:

sections,vmsize,filesize
.debug_info,0,191
.debug_str,0,75
.strtab,0,42
.debug_abbrev,0,41
.symtab,0,32
.debug_aranges,0,8
[Unmapped],0,8
.debug_frame,0,4
.shstrtab,0,-2
.text,-8,-8
.debug_ranges,0,-32
.debug_line,0,-78
.debug_loc,0,-737

Comparing ./master_artifact/chip-qpg6100-lighting-example.out.map and ./pull_artifact/chip-qpg6100-lighting-example.out.map:

BLOAT EXECUTION FAILED WITH CODE 1:
bloaty: unknown file type for file './pull_artifact/chip-qpg6100-lighting-example.out.map'

[bzbarsky-apple]

@Damian-Nordic @jmartinez-silabs Please take a look?