msm: sdio_ctl: Update the driver to support poll operation

Poll operation is needed by user-space modules, to select among
multiple file descriptors for read/write operation.

CRs-Fixed: 357121
Change-Id: Iaa817c31bdfee7a1fcb3c5e94a805a526b71cd6c
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>