vp10/ratectrl.c: fix implicit float conversion
vp10/ratectrl.c: fix implicit float conversion

float->int as reported by -Wfloat-conversion

Change-Id: I3c55990821d922bda7a7600c00ae8d5dcc3cee94

mbebenita/aom,mbebenita/aom,smarter/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,GrokImageCompression/aom,GrokImageCompression/aom,mbebenita/aom,smarter/aom,smarter/aom,GrokImageCompression/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,luctrudeau/aom,mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom