drivers/net/wireless/mwifiex/scan.c: convert GFP_KERNEL to GFP_ATOMIC

The function is called with locks held and thus should not use GFP_KERNEL.

The semantic patch that makes this report is available
in scripts/coccinelle/locks/call_kern.cocci.

More information about semantic patching is available at
http://coccinelle.lip6.fr/

Signed-off-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>