avcodec/mips/cabac: Fix a bug in get_cabac_inline_mips.

Failed fate case: fate-h264-conformance-caba2_sony_e
Clang is more strict in the use of register constraint.
Signed-off-by: NMichael Niedermayer <michael@niedermayer.cc>

libavcodec/mips/cabac.h

@@ -109,7 +109,7 @@ static av_always_inline int get_cabac_inline_mips(CABACContext *c,
       [lps_off]"i"(H264_LPS_RANGE_OFFSET),
       [mlps_off]"i"(H264_MLPS_STATE_OFFSET + 128),
       [norm_off]"i"(H264_NORM_SHIFT_OFFSET),
-      [cabac_mask]"i"(CABAC_MASK)
+      [cabac_mask]"r"(CABAC_MASK)
     : "memory"
     );