spi_qsd: correct the chip select gpios valid field entry

During probe Chip select gpio's valid field is set to non-zero.
This is causing gpio free to get called for not-used gpios
during runtime suspend.

CRs-Fixed: 525743
Change-Id: Ib0de417d640f30908ad11650b584833dac286646
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>