alpha: build fixes - force architecture

Override compiler .arch directive for generic kernel build.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/alpha/kernel/sys_titan.c b/arch/alpha/kernel/sys_titan.c
index 29ab7db..f009b7b 100644
--- a/arch/alpha/kernel/sys_titan.c
+++ b/arch/alpha/kernel/sys_titan.c
@@ -257,8 +257,7 @@
 	 */
 	while (mask) {
 		/* convert to SRM vector... priority is <63> -> <0> */
-		__asm__("ctlz %1, %0" : "=r"(vector) : "r"(mask));
-		vector = 63 - vector;
+		vector = 63 - __kernel_ctlz(mask);
 		mask &= ~(1UL << vector);	/* clear it out 	 */
 		vector = 0x900 + (vector << 4);	/* convert to SRM vector */