aarch64: vp8: Port bilin functions from arm version

aarch64: vp8: Port bilin functions from arm version

                      Cortex A53     A72     A73
vp8_put_bilin4_h_c:        303.8   102.2   161.8
vp8_put_bilin4_h_neon:     100.0    40.9    41.2
vp8_put_bilin4_hv_c:       322.8   201.0   305.9
vp8_put_bilin4_hv_neon:    156.8    72.6    77.0
vp8_put_bilin4_v_c:        304.7   101.7   166.5
vp8_put_bilin4_v_neon:      82.7    41.2    33.0
vp8_put_bilin8_h_c:       1192.7   352.5   623.8
vp8_put_bilin8_h_neon:     213.5    70.2    87.8
vp8_put_bilin8_hv_c:      1098.6   769.2  1041.9
vp8_put_bilin8_hv_neon:    324.0   123.5   146.0
vp8_put_bilin8_v_c:       1193.9   350.4   617.7
vp8_put_bilin8_v_neon:     183.9    60.7    64.7
vp8_put_bilin16_h_c:      2353.1   671.2  1223.3
vp8_put_bilin16_h_neon:    261.9   140.7   145.0
vp8_put_bilin16_hv_c:     2453.2  1470.9  2355.2
vp8_put_bilin16_hv_neon:   383.9   196.0   217.0
vp8_put_bilin16_v_c:      2349.3   669.8  1251.2
vp8_put_bilin16_v_neon:    202.9   110.7    96.2

Signed-off-by: Martin Storsjö <martin@martin.st>