Use 'E' instead of 'X' for unsigned module taint flag.

Takashi Iwai <tiwai@suse.de> says:
> The letter 'X' has been already used for SUSE kernels for very long
> time, to indicate the external supported modules.  Can the new flag be
> changed to another letter for avoiding conflict...?
> (BTW, we also use 'N' for "no support", too.)

Note: this code should be cleaned up, so we don't have such maps in
three places!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/panic.c b/kernel/panic.c
index 0e25fe1..02b6c9f 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -210,7 +210,7 @@
 	{ TAINT_CRAP,			'C', ' ' },
 	{ TAINT_FIRMWARE_WORKAROUND,	'I', ' ' },
 	{ TAINT_OOT_MODULE,		'O', ' ' },
-	{ TAINT_UNSIGNED_MODULE,	'X', ' ' },
+	{ TAINT_UNSIGNED_MODULE,	'E', ' ' },
 };
 
 /**
@@ -229,7 +229,7 @@
  *  'C' - modules from drivers/staging are loaded.
  *  'I' - Working around severe firmware bug.
  *  'O' - Out-of-tree module has been loaded.
- *  'X' - Unsigned module has been loaded.
+ *  'E' - Unsigned module has been loaded.
  *
  *	The string is overwritten by the next call to print_tainted().
  */