KVM: x86: add asm_safe wrapper

KVM: x86: add asm_safe wrapper

BugLink: http://bugs.launchpad.net/bugs/1658091
commit aabba3c6abd50b05b1fc2c6ec44244aa6bcda576 upstream.

Move the existing exception handling for inline assembly into a macro
and switch its return values to X86EMUL type.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>