ARM: add ARMv6 optimised av_clip_uintp2

Signed-off-by: Mans Rullgard <mans@mansr.com>

libavutil/arm/intmath.h

@@ -74,6 +74,15 @@ static av_always_inline av_const int16_t av_clip_int16_arm(int a)
     return x;
 }
 
+#define av_clip_uintp2 av_clip_uintp2_arm
+static av_always_inline av_const unsigned av_clip_uintp2_arm(int a, int p)
+{
+    unsigned x;
+    __asm__ ("usat %0, %2, %1" : "=r"(x) : "r"(a), "i"(p));
+    return x;
+}
+
+
 #else /* HAVE_ARMV6 */
 
 #define FASTDIV FASTDIV