Rename xvmc.c --> mpegvideo_xvmc.c as suggested by Ivan.

Originally committed as revision 17228 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/Makefile

@@ -252,7 +252,7 @@ OBJS-$(CONFIG_XAN_WC3_DECODER)         += xan.o
 OBJS-$(CONFIG_XAN_WC4_DECODER)         += xan.o
 OBJS-$(CONFIG_XL_DECODER)              += xl.o
 OBJS-$(CONFIG_XSUB_DECODER)            += xsubdec.o
-OBJS-$(CONFIG_XVMC)                    += xvmc.o
+OBJS-$(CONFIG_XVMC)                    += mpegvideo_xvmc.o
 OBJS-$(CONFIG_ZLIB_DECODER)            += lcldec.o
 OBJS-$(CONFIG_ZLIB_ENCODER)            += lclenc.o
 OBJS-$(CONFIG_ZMBV_DECODER)            += zmbv.o