sim: move UNUSED before TYPE in SIM_ENDIAN_INLINE's definition

sim: move UNUSED before TYPE in SIM_ENDIAN_INLINE's definition

I get this when building with gcc 11:

      CC       common/common_libcommon_a-sim-load.o
    In file included from /home/simark/src/binutils-gdb/sim/common/sim-n-bits.h:27,
                     from /home/simark/src/binutils-gdb/sim/common/sim-bits.c:259,
                     from /home/simark/src/binutils-gdb/sim/common/sim-bits.h:599,
                     from /home/simark/src/binutils-gdb/sim/common/sim-basics.h:122,
                     from /home/simark/src/binutils-gdb/sim/common/sim-load.c:30:
    /home/simark/src/binutils-gdb/sim/common/sim-n-endian.h:39:27: error: 'offset_16' defined but not used [-Werror=unused-function]
       39 | #define offset_N XCONCAT2(offset_,N)
          |                           ^~~~~~~
    /home/simark/src/binutils-gdb/sim/../include/symcat.h:23:26: note: in definition of macro 'CONCAT2'
       23 | #define CONCAT2(a,b)     a##b
          |                          ^
    /home/simark/src/binutils-gdb/sim/common/sim-n-endian.h:39:18: note: in expansion of macro 'XCONCAT2'
       39 | #define offset_N XCONCAT2(offset_,N)
          |                  ^~~~~~~~
    /home/simark/src/binutils-gdb/sim/common/sim-n-endian.h:138:1: note: in expansion of macro 'offset_N'
      138 | offset_N (unsigned_N *x,
          | ^~~~~~~~

offset_N uses INLINE_SIM_ENDIAN, which uses UNUSED to put the "unused"
attribute.  However, it appears after the function's return type, which
seems to make it not apply to the function.  Moving it to before the
return type fixes the error.

Change all instances found in that file.

sim/common/ChangeLog:

	* sim-inline.h: Move UNUSED before TYPE.

Change-Id: Ide20106683ed7a9ebf35d484dabf70b309cb1ba6