x86/emul: Correct the decoding of vlddqu

x86/emul: Correct the decoding of vlddqu

vlddqu is encoded with 0xf2 which causes it to fall into the Scalar general
case in x86_decode_twobyte().  However, it really does have just two operands,
so must remain TwoOp

AFL discovered that the instruction c5 5b f0 3c e5 95 0a cd 63 was considered
valid despite it being a two operand instruction and VEX.vvvv having the value
11.  The resulting use in a stub yielded #UD.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>