brcm80211: cypress: Use a generic CYW43455 firmware

Cypress/Infineon have recommended switching to their standard firmware
releases henceforth. This firmware (version [1]) has the advantage of
supporting WPA3 authentication, allowing Pis to connect to WPA3-only
APs.

[1] 43455c0-roml/43455_sdio-pno-aoe-pktfilter-pktctx-wfds-mfp-dfsradar-wowlpf-idsup-idauth-noclminc-clm_min-obss-obssdump-swdiv-gtkoe-roamprof-txbf-ve-sae-dpp-sr-okc-bpd Version: 7.45.234 (4ca95bb CY) CRC: 212e223d Date: Thu 2021-04-15 03:06:00 PDT Ucode Ver: 1043.2161 FWID 01-996384e2

Signed-off-by: Phil Elwell <[email protected]>