mwifiex: Disable adhoc feature based on firmware capability

We will read fw_cap_info filled by firmware to check whether to
skip ADHOC related commands or not. Also, IBSS_COALESCING_STATUS
command has been moved from init path to adhoc network creation
path.

Signed-off-by: Karthik D A <karthida@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>