Fix Visual Studio build failure in filter_selectively_vert_row2() calls

Fix Visual Studio build failure in filter_selectively_vert_row2() calls

Error messages:
 ..\vp9\common\vp9_loopfilter.c(1312): warning C4244: 'function' :
conversion from 'uint64_t' to 'unsigned int', possible loss of data
[.build-x86_64-win64-vs10\vpx.vcxproj]

..\vp9\common\vp9_loopfilter.c(1313): warning C4244: 'function' :
conversion from 'uint64_t' to 'unsigned int', possible loss of data
[.build-x86_64-win64-vs10\vpx.vcxproj]

..\vp9\common\vp9_loopfilter.c(1312): error C2220: warning treated as
error - no 'object' file generated
[.build-x86_64-win64-vs10\vpx.vcxproj]

Change-Id: Ia69260611997cd2ba41c7184a85ecead740a7c07