mwifiex: Move code for wowlan magic-packet and patterns to a function

This patch moves code for wowlan magic-packet and patterns to a function
mwifiex_set_mef_filter.

Signed-off-by: Maithili Hinge <maithili@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>