MIPS: Use BUG_ON() where possible.

Based on original patch by Stoyan Gaydarov <stoyboyker@gmail.com> which
missed a few places.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/traps.c

@@ -1277,8 +1277,7 @@ static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
 	u32 *w;
 	unsigned char *b;
 
-	if (!cpu_has_veic && !cpu_has_vint)
-		BUG();
+	BUG_ON(!cpu_has_veic && !cpu_has_vint);
 
 	if (addr == NULL) {
 		handler = (unsigned long) do_default_vi;