spi: ti_qspi: Remove delay in read path for dra7xx

As per commit b545a98f ("spi: ti_qspi: Add delay
for successful bulk erase) says its added to meet bulk erase timing
constraints. But bulk erase is a cmd to flash and delay in read path
does not make sense. Morever, testing on DRA74/DRA72 evm has shown that
this delay is no longer required.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>