mips/syscall-error: Choose the correct version for setting up errno.

mips/syscall-error: Choose the correct version for setting up errno.

* Current function is a C protype and PSEUDO macro does not
  transfer syscall return parameters to correct argument registers
  for a C function. This causes problem with syscalls setting wrong
  value for errno when they encounter an error.

* Fixes PR/2089 for mips/nptl

Signed-off-by: Khem Raj <raj.khem@gmail.com>