wl12xx: allow runtime changing of debug_level

Currently, the debug level is set in compilation time (by the DEBUG_LEVEL
const). This method has the advantage of compiling only the relevant
messages, while optimizing out the unused ones.

In order to allow runtime control over the debug_level, while optimizing
out messages when debug messages are not needed, we combine some methods:
1. use dynamic_debug (pr_debug) rather then printk.
2. add debug_level module param in order to set debug level during insmod.
3. add debug_level sysfs file in order to allow dynamic control over the
   debug level.

Since patches for pr_debug_hex_dump() implementation haven't been applied yet,
we are still temporarly using print_hex_dump().

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
diff --git a/drivers/net/wireless/wl12xx/debugfs.c b/drivers/net/wireless/wl12xx/debugfs.c
index 8106a6c..c2cd580 100644
--- a/drivers/net/wireless/wl12xx/debugfs.c
+++ b/drivers/net/wireless/wl12xx/debugfs.c
@@ -401,6 +401,11 @@
 
 	DEBUGFS_ADD(gpio_power, wl->rootdir);
 
+	entry = debugfs_create_x32("debug_level", 0600, wl->rootdir,
+				   &wl12xx_debug_level);
+	if (!entry || IS_ERR(entry))
+		goto err;
+
 	return 0;
 
 err: