brcmfmac: Add BCM43454/6 support

BCM43454/6 is a variant of BCM4345 which is exactly identical to
BCM4345/6, except the chip id is 0xa9be. This patch adds support
for BCM43454/6 by handing it in the same way as BCM4345.

Note: when loading some specific version of BCM4345 firmware, the
chip id may become 0x4345. This is an expected behavior, and it will
restore to 0xa9be after power cycle.

Signed-off-by: Jiaqing Zhao <jiaqing.zhao@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/CO1PR11MB47859B51BCA88613D1582EB88E2E9@CO1PR11MB4785.namprd11.prod.outlook.com