parisc: Convert BUG() to use unreachable()

Use the new unreachable() macro instead of for(;;);

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

arch/parisc/include/asm/bug.h

@@ -32,14 +32,14 @@
 			     "\t.popsection"				\
 			     : : "i" (__FILE__), "i" (__LINE__),	\
 			     "i" (0), "i" (sizeof(struct bug_entry)) ); \
-		for(;;) ;						\
+		unreachable();						\
 	} while(0)
 
 #else
 #define BUG()								\
 	do {								\
 		asm volatile(PARISC_BUG_BREAK_ASM : : );		\
-		for(;;) ;						\
+		unreachable();						\
 	} while(0)
 #endif