staging: brcm80211: Better debug support added to brcmfmac driver

With the current implementation there is no way to selectively enable
required debug messages, as all the messages are currently under WL_DBG.
With this fix, we are introducing several log levels which will enable
us to print only the required debug messages.
WL_ERR --> Prints error messages
WL_CONN --> Prints all debug messages pertaining to connection
management
WL_SCAN --> Prints all debug messages pertaining to scanning
WL_TRACE --> Prints all trace(Enter/Exit) sequence of cfg80211 calls
WL_INFO --> Prints all informational messages.
By default, only WL_ERR messages are enabled.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>