target/i386: svm: do not discard high 32 bits of EXITINFO1

target/i386: svm: do not discard high 32 bits of EXITINFO1

env->error_code is only 32-bits wide, so the high 32 bits of EXITINFO1
are being lost.  However, even though saving guest state and restoring
host state must be delayed to do_vmexit, because they might take tb_lock,
it is always possible to write to the VMCB.  So do this for the exit
code and EXITINFO1, just like it is already being done for EXITINFO2.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>