x86.h,x86_simd_caps: add an explicit cast w/strtol
x86.h,x86_simd_caps: add an explicit cast w/strtol

+ use strtoul as mask is unsigned

quiets a -Wshorten-64-to-32 warning

Change-Id: Ia1c24679302100a252da7a45d3bb871f591f1888

webmproject/libvpx,mbebenita/aom,mwgoldsmith/vpx,GrokImageCompression/aom,mbebenita/aom,mwgoldsmith/vpx,mbebenita/aom,Topopiccione/libvpx,webmproject/libvpx,GrokImageCompression/aom,mbebenita/aom,smarter/aom,GrokImageCompression/aom,Topopiccione/libvpx,mbebenita/aom,mwgoldsmith/libvpx,GrokImageCompression/aom,mwgoldsmith/libvpx,smarter/aom,mwgoldsmith/vpx,mbebenita/aom,mwgoldsmith/libvpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,Topopiccione/libvpx,mbebenita/aom,mwgoldsmith/libvpx,Topopiccione/libvpx,luctrudeau/aom,mwgoldsmith/vpx,luctrudeau/aom,ShiftMediaProject/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,mbebenita/aom,GrokImageCompression/aom,ShiftMediaProject/libvpx,Topopiccione/libvpx,webmproject/libvpx,smarter/aom,ShiftMediaProject/libvpx,luctrudeau/aom,mbebenita/aom,ShiftMediaProject/libvpx,mwgoldsmith/vpx,luctrudeau/aom,webmproject/libvpx,luctrudeau/aom,mwgoldsmith/libvpx,luctrudeau/aom,webmproject/libvpx,smarter/aom,webmproject/libvpx,smarter/aom,GrokImageCompression/aom,smarter/aom