rtlwifi: add CONFIG_RTLWIFI_DEBUG to remove all of the debug logging code

It does seem odd though to have a DBG_EMERG and not always
emit it.

What might also be useful for any embedded use is to add
CONFIG_RTLWIFI_DEBUG to conditionally remove all of the
debug logging code to reduce the largish object size.

This reduces the object size by about 1/3 (250KB)
when CONFIG_RTLWIFI_DEBUG is not set.

$ size drivers/net/wireless/rtlwifi/built-in.o*
   text	   data	    bss	    dec	    hex	filename
 368722	  55333	  94224	 518279	  7e887	drivers/net/wireless/rtlwifi/built-in.o.new
 586904	  55333	 127216	 769453	  bbdad	drivers/net/wireless/rtlwifi/built-in.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rtlwifi/Kconfig b/drivers/net/wireless/rtlwifi/Kconfig
index d6c42e6..44b9c0a 100644
--- a/drivers/net/wireless/rtlwifi/Kconfig
+++ b/drivers/net/wireless/rtlwifi/Kconfig
@@ -49,6 +49,11 @@
 	depends on RTL8192CE || RTL8192CU || RTL8192SE || RTL8192DE
 	default m
 
+config RTLWIFI_DEBUG
+	tristate "Additional debugging output"
+	depends on RTL8192CE || RTL8192CU || RTL8192SE || RTL8192DE
+	default y
+
 config RTL8192C_COMMON
 	tristate
 	depends on RTL8192CE || RTL8192CU