go-1.4.3 supports only 386, amd64, arm (32-bit) so:
- remove mips*, the specs are incomplete even for later mips-aware
versions of go;
- pass correct option for 386 FPU, otherwise it is autodetected at
build time (to sse2);
- pass ARM architecture version explicitly for arm*;
This change affects the x86 package so bump pkgrel.