staging/brcm80211: Fix common spelling mistakes

This patch fixes some very common spelling mistakes in
drivers/staging/brcm80211.

WRONG -> RIGHT
accomodate  -> accommodate
occured     -> occurred
recieve     -> receive
unferflow	-> underflow
useable		-> usable

Kernel Version: staging/staging-next 20110325 (4bbba111)

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>