x86emul: add support for missing {,V}PMADDWD insns

Their pre-AVX512 incarnations have clearly been overlooked during much
earlier work. Their memory access pattern is entirely standard, so no
specific tests get added to the harness.
Reported-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Alexandru Isaila <aisaila@bitdefender.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/x86_emulate/x86_emulate.c

@@ -6624,6 +6624,8 @@ x86_emulate(
     case X86EMUL_OPC_VEX_66(0x0f, 0xf3): /* vpsllq xmm/m128,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_66(0x0f, 0xf4):     /* pmuludq xmm/m128,xmm */
     case X86EMUL_OPC_VEX_66(0x0f, 0xf4): /* vpmuludq {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    CASE_SIMD_PACKED_INT(0x0f, 0xf5):    /* pmaddwd {,x}mm/mem,{,x}mm */
+    case X86EMUL_OPC_VEX_66(0x0f, 0xf5): /* vpmaddwd {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_66(0x0f, 0xf6):     /* psadbw xmm/m128,xmm */
     case X86EMUL_OPC_VEX_66(0x0f, 0xf6): /* vpsadbw {x,y}mm/mem,{x,y}mm,{x,y}mm */
     CASE_SIMD_PACKED_INT(0x0f, 0xf8):    /* psubb {,x}mm/mem,{,x}mm */