Fix compliation on gcc-4.3 and ARMv5T

- smulbb is only on ARMv5TE and above (p316, ARM Architecture Reference Manual)
 - an empty clobber list causes a compiler error with my compiler, gcc-4.3.2

Patch by Joel Stanley <joel@jms.id.au>

Review URL: http://codereview.appspot.com/96165


git-svn-id: http://skia.googlecode.com/svn/trunk@329 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkMath.h

@@ -162,7 +162,10 @@ static inline int SkNextLog2(uint32_t value) {
     With this requirement, we can generate faster instructions on some
     architectures.
 */
-#if defined(__arm__) && !defined(__thumb__) && !defined(__ARM_ARCH_4__)
+#if defined(__arm__) \
+  && !defined(__thumb__) \
+  && !defined(__ARM_ARCH_4__) \
+  && !defined(__ARM_ARCH_5T__)
     static inline int32_t SkMulS16(S16CPU x, S16CPU y) {
         SkASSERT((int16_t)x == x);
         SkASSERT((int16_t)y == y);
@@ -170,7 +173,6 @@ static inline int SkNextLog2(uint32_t value) {
         asm("smulbb %0, %1, %2 \n"
             : "=r"(product)
             : "r"(x), "r"(y)
-            :
             );
         return product;
     }