Update the MIPS main loop code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn

(We already handle TARGET_QEMU_ESIGRETURN.)
Signed-off-by: NTimothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-7-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>