Turn some inter recon functions static.
Turn some inter recon functions static.

Makes the following functions static since they are not used outside
inter.c:
- kvz_inter_recon_frac_luma
- kvz_inter_recon_14bit_frac_luma
- kvz_inter_recon_frac_chroma
- kvz_inter_recon_14bit_frac_chroma

ultravideo/kvazaar,ultravideo/kvazaar,ultravideo/kvazaar,ultravideo/kvazaar,ultravideo/kvazaar