lavc/aarch64: add a few SIMD functions for AAC PS

☭ tests/checkasm/checkasm --bench --test=aacpsdsp
checkasm: using random seed 3318985180
MMX implied by specified flags
MMX implied by specified flags
NEON:
 - aacpsdsp.add_squares        [OK]
 - aacpsdsp.mul_pair_single    [OK]
 - aacpsdsp.hybrid_analysis    [OK]
 - aacpsdsp.stereo_interpolate [OK]
checkasm: all 5 tests passed
nop: 10.0
ps_add_squares_c: 63221.2
ps_add_squares_neon: 22311.7
ps_hybrid_analysis_c: 2466.6
ps_hybrid_analysis_neon: 1521.9
ps_mul_pair_single_c: 68592.0
ps_mul_pair_single_neon: 17426.6
ps_stereo_interpolate_c: 72344.3
ps_stereo_interpolate_neon: 72308.8
ps_stereo_interpolate_ipdopd_c: 117415.2
ps_stereo_interpolate_ipdopd_neon: 113386.3