spi: bcm-qspi: Add mspi spcr3 32/64-bits xfer mode

Adding 32-bits and 64-bits per transfer modes using the SPCR3
register settings provided in MSPI controller ver >= 1.5

Signed-off-by: Kamal Dasu <kdasu@broadcom.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20211008203603.40915-2-kdasu.kdev@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>