mn10300.c (expand_prologue): Rework to avoid unnecessary "add" operations.

mn10300.c (expand_prologue): Rework to avoid unnecessary "add" operations.

        * mn10300/mn10300.c (expand_prologue): Rework to avoid unnecessary
        "add" operations.
        (expand_epilogue): Likewise.
        * mn10300/mn10300.h (STARTING_FRAME_OFFSET): Is zero after the last
        round of prologue/epilogue changes.
        (FIRST_PARM_OFFSET): Is now 16 (-4 for REG_PARM_STACK_SPACE + 20 for
        register save area).
        (REG_PARM_STACK_SPACE): Define as 4 bytes.
        (OUTGOING_REG_PARM_STACK_SPACE): Define so caller allocates it.
        * mn10300/mn10300.md (call expander): Don't emit insns to adjust the
        stack here anymore.
        (call_value expander): Likewise.

        * mn10300/mn10300.md (bCC patterns): Just use "bCC target" now that
        the assembler handles relaxing.

From-SVN: r13696