xtensa: fix RASID SR initialization

set_rasid_register accepts new RASID SR value, but ASID_USER_FIRST is
ASID value for the ring 1; RASID value is made by ASID_INSERT macro.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/mm/mmu.c

@@ -37,7 +37,7 @@ void __init init_mmu(void)
 
 	/* Set rasid register to a known value. */
 
-	set_rasid_register(ASID_USER_FIRST);
+	set_rasid_register(ASID_INSERT(ASID_USER_FIRST));
 
 	/* Set PTEVADDR special register to the start of the page
 	 * table, which is in kernel mappable space (ie. not