libswscale: fix for floating point formats, require full chroma

upon more floating point testing, looks like I missed adding this bit.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libswscale/utils.c

@@ -1405,6 +1405,8 @@ av_cold int sws_init_context(SwsContext *c, SwsFilter *srcFilter,
         srcFormat != AV_PIX_FMT_GBRP14BE  && srcFormat != AV_PIX_FMT_GBRP14LE &&
         srcFormat != AV_PIX_FMT_GBRP16BE  && srcFormat != AV_PIX_FMT_GBRP16LE &&
         srcFormat != AV_PIX_FMT_GBRAP16BE  && srcFormat != AV_PIX_FMT_GBRAP16LE &&
+        srcFormat != AV_PIX_FMT_GBRPF32BE  && srcFormat != AV_PIX_FMT_GBRPF32LE &&
+        srcFormat != AV_PIX_FMT_GBRAPF32BE && srcFormat != AV_PIX_FMT_GBRAPF32LE &&
         ((dstW >> c->chrDstHSubSample) <= (srcW >> 1) ||
          (flags & SWS_FAST_BILINEAR)))
         c->chrSrcHSubSample = 1;