KVM: x86 emulator: Add support for mov seg, r (0x8e) instruction

Add support for mov r, sreg (0x8c) instruction.

[avi: drop the sreg decoding table in favor of 1:1 encoding]

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Laurent Vivier <laurent.vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>