brcmfmac: Restore ISO3166 and 0 rev as a fallback

Commit b0b524f0 ("brcmfmac: use ISO3166 country code and 0 rev
as fallback") was a welcome addition for Raspberry Pi as it replaced
an equivalent bit of downstream code. Commit 151a7c12 reverted
it because it broke BCM4359/9 devices.

This is a renamed reversion of the reversion.

See: https://github.com/raspberrypi/Raspberry-Pi-OS-64bit/issues/217



Signed-off-by: Phil Elwell <phil@raspberrypi.com>