driver: spi: add bcm iproc qspi support

IPROC qspi driver supports both BSPI and MSPI modes.

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: Bharat Gooty <bharat.gooty@broadcom.com>
Acked-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>

Signed-off-by: Roman Bacik <roman.bacik@broadcom.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>