staging: unisys: remove unused variable

we were getting lots of warnings about _tempresult set but not used.
_tempresult was used in the macro ISSUE_IO_VMCALL_POSTCODE_SEVERITY
which was again using another macro ISSUE_IO_EXTENDED_VMCALL.
but the value assigned to it was never used.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>