mwifiex: disable channel filtering for SSID specific scan from user

If MWIFIEX_DISABLE_CHAN_FILT bit in scan mode bitmap is set,
firmware will turn off the filtering of scan responses from
adjacent channels.

Currently the bit is set only for internal SSID specific scan
performed during association. We will set it for user requested
SSID specific scan as well.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>