mwifiex: restore current SDIO write port in failure cases

During SDIO MP aggregation, we at first acquire current write
port to write data onto and then proceed with using this port
for SDIO write. If error occurs later in mwifiex_write_data_sync
because device is suspended or SDIO write failure, we do not
restore current write port and write bitmap. This results into
leaking one port and hole in SDIO write port bitmap.
Restore current write port and reset bitmap accordingly in
failure cases to avoid this.

Reported-by: James Cameron <quozl@laptop.org>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Reviewed-by: James Cameron <quozl@laptop.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>