spi: cadence_qspi: Use #define for bits instead of bit shifts

Most of the code already uses #defines for the bit value, rather
than the shift required to get the value. This changes the remaining
code over.

Whislt at it, fix the names of the "Rd Data Capture" register defs.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>