mwifiex: fix AP VHT behaviour

Even if hostapd configuration file contains VHT parameters,
they were not getting reflected in beacons. The reason is
we are resetting them before starting AP. This patch removes
redundant BSS_STOP and SYS_RESET firmware commands before
starting AP to fix the problem.

Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>