[Silabs] Silabs fix pigweed

[jepenven-silabs]

Fix Pigweed rpc. Problem is that pigweed ONLY send commands and output byte by byte which is sub-optimal with the new uart implementation. Add a bypass for pigweed rpc only.

[github-actions]

PR #25929: Size comparison from 3f0e043 to 5dfbbf8

Increases (2 builds for cc32xx, qpg)

platform	target	config	section	3f0e043	5dfbbf8	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_info	20310330	20310331	1	0.0
qpg	lock-app	qpg6105+debug	(read/write)	1121544	1121552	8	0.0
			.text	568644	568652	8	0.0

Full report (4 builds for cc32xx, mbed, qpg)

platform	target	config	section	3f0e043	5dfbbf8	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	645825	645825	0	0.0
			(read/write)	203848	203848	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197248	197248	0	0.0
			.comment	194	194	0	0.0
			.data	1480	1480	0	0.0
			.debug_abbrev	933102	933102	0	0.0
			.debug_aranges	87704	87704	0	0.0
			.debug_frame	301596	301596	0	0.0
			.debug_info	20310330	20310331	1	0.0
			.debug_line	2681125	2681125	0	0.0
			.debug_loc	2827568	2827568	0	0.0
			.debug_ranges	286448	286448	0	0.0
			.debug_str	3041144	3041144	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	105953	105953	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	380543	380543	0	0.0
			.symtab	257472	257472	0	0.0
			.text	537752	537752	0	0.0
mbed	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2466536	2466536	0	0.0
			.bss	215964	215964	0	0.0
			.data	5880	5880	0	0.0
			.text	1429180	1429180	0	0.0
qpg	lighting-app	qpg6105+debug	(read/write)	1152976	1152976	0	0.0
			.bss	96036	96036	0	0.0
			.data	852	852	0	0.0
			.text	600072	600072	0	0.0
	lock-app	qpg6105+debug	(read/write)	1121544	1121552	8	0.0
			.bss	91172	91172	0	0.0
			.data	856	856	0	0.0
			.text	568644	568652	8	0.0

[github-actions]

PR #25929: Size comparison from 7ccd5d4 to 72303a0

Increases (1 build for cc32xx)

platform	target	config	section	7ccd5d4	72303a0	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_info	20310330	20310331	1	0.0

Full report (1 build for cc32xx)

platform	target	config	section	7ccd5d4	72303a0	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	645825	645825	0	0.0
			(read/write)	203848	203848	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197248	197248	0	0.0
			.comment	194	194	0	0.0
			.data	1480	1480	0	0.0
			.debug_abbrev	933102	933102	0	0.0
			.debug_aranges	87704	87704	0	0.0
			.debug_frame	301596	301596	0	0.0
			.debug_info	20310330	20310331	1	0.0
			.debug_line	2681125	2681125	0	0.0
			.debug_loc	2827568	2827568	0	0.0
			.debug_ranges	286448	286448	0	0.0
			.debug_str	3041144	3041144	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	105953	105953	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	380543	380543	0	0.0
			.symtab	257472	257472	0	0.0
			.text	537752	537752	0	0.0