brcm80211: Use normal DEBUG define

Current CONFIG_BRCMDBG flag when enabled does not
necessarily enable proper pr_debug output when
DEBUG is not also enabled.

Remove BCMDBG define and just use DEBUG instead.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>