signal/xtensa: Consistenly use SIGBUS in do_unaligned_user

While working on changing this code to use force_sig_fault I
discovered that do_unaliged_user is sets si_signo to SIGBUS and passes
SIGSEGV to force_sig_info.  Which is just b0rked.

The code is reporting a SIGBUS error so replace the SIGSEGV with SIGBUS.

Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
Cc: stable@vger.kernel.org
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Fixes: 5a0015d6 ("[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 3")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

arch/xtensa/kernel/traps.c

@@ -339,7 +339,7 @@ do_unaligned_user (struct pt_regs *regs)
 	info.si_errno = 0;
 	info.si_code = BUS_ADRALN;
 	info.si_addr = (void *) regs->excvaddr;
-	force_sig_info(SIGSEGV, &info, current);
+	force_sig_info(SIGBUS, &info, current);
 
 }
 #endif