mwifiex: fix checkpatch --strict warnings/errors Part 3

For files fw.h, init.c and join.c

Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>