x86: replace EX{d,q}Scalar by EXxmm_m{d,q}

x86: replace EX{d,q}Scalar by EXxmm_m{d,q}

Along the lines of 4102be5cf925 ("x86: replace EXxmm_mdq by
EXVexWdqScalar"), but in the opposite direction, replace EXdScalar/
EXqScalar by EXxmm_md/EXxmm_mq respectively, rendering d_scalar_mode and
q_scalar_mode unused. The change is done this way to improve telling
apart operands affected here from ones using EXbScalar/EXwScalar, which
work sufficiently differently. Additionally this increases similarity
between several VEX-encoded insns and their EVEX-encoded counterparts.