wifi: brcmfmac: common: Add support for external calibration blobs

The calibration blob for a chip is normally stored in SROM and loaded
internally by the firmware. However, Apple ARM64 platforms instead store
it as part of platform configuration data, and provide it via the Apple
Device Tree. We forward this into the Linux DT in the bootloader.

Add support for taking this blob from the DT and loading it into the
dongle. The loading mechanism is the same as used for the CLM and TxCap
blobs.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230214092423.15175-10-marcan@marcan.st