This enables user to check beacon interval, DTIM period, short slot
time and short preamble information using "iw dev mlan0 link" command
when station is in connected state.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>