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>
diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c
index 8f2cd8e..060d28d 100644
--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -17,8 +17,7 @@
 
 void __kunmap(struct page *page)
 {
-	if (in_interrupt())
-		BUG();
+	BUG_ON(in_interrupt());
 	if (!PageHighMem(page))
 		return;
 	kunmap_high(page);
@@ -46,8 +45,7 @@
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
-	if (!pte_none(*(kmap_pte-idx)))
-		BUG();
+	BUG_ON(!pte_none(*(kmap_pte - idx)));
 #endif
 	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
 	local_flush_tlb_one((unsigned long)vaddr);
@@ -66,8 +64,7 @@
 		return;
 	}
 
-	if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx))
-		BUG();
+	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
 
 	/*
 	 * force other mappings to Oops if they'll try to access