spi: cadence_qspi_apb: Support 32 bit AHB address

AHB address can be as long as 32 bit, hence remove the
CQSPI_REG_INDIRECTRDSTARTADDR mask. Since AHB address is passed from DT
and read as u32 value, it anyway does not make sense to mask upper bits.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Tested-by: Marek Vasut <marex@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>