sparc/leon: add support for partial write psr instruction

sparc/leon: add support for partial write psr instruction

Partial write %PSR (PWRPSR) is a SPARC V8e option that allows the WRPSR
instruction to only affect the %PSR.ET field. When available it is enabled
by setting the rd field of the WRPSR instruction to a value other than 0.
For Leon processors with support for partial write %PSR (currently GR740
and GR716) the rd value must be 1.

opcodes/ChangeLog:

2018-08-29  Martin Aberg  <maberg@gaisler.com>

        * sparc-opc.c (sparc_opcodes): Add Leon specific partial write
        psr (PWRPSR) instruction.

gas/ChangeLog:

2018-08-29  Daniel Cederman  <cederman@gaisler.com>

        * testsuite/gas/sparc/leon.d: New test.
        * testsuite/gas/sparc/leon.s: New test.
        * testsuite/gas/sparc/sparc.exp: Execute the pwrpsr test.