parisc: math-emu: Avoid "fmt" macro collision

The printk "fmt" macro was colliding. Rename like the others with a
"bits" suffix. Fixes a build failure:

arch/parisc/math-emu/decode_exc.c: In function 'decode_fpu':
arch/parisc/math-emu/decode_exc.c:49:14: error: expected identifier before numeric constant
   49 | #define fmt  11 /* bits 19 & 20 */
      |              ^~
./include/linux/printk.h:379:6: note: in expansion of macro 'fmt'
  379 |     .fmt = __builtin_constant_p(_fmt) ? (_fmt) : NULL, \
      |      ^~~
./include/linux/printk.h:417:3: note: in expansion of macro '__printk_index_emit'
  417 |   __printk_index_emit(_fmt, NULL, NULL);   \
      |   ^~~~~~~~~~~~~~~~~~~
./include/linux/printk.h:446:26: note: in expansion of macro 'printk_index_wrap'
  446 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
      |                          ^~~~~~~~~~~~~~~~~
arch/parisc/math-emu/decode_exc.c:339:3: note: in expansion of macro 'printk'
  339 |   printk("%s(%d) Unknown FPU exception 0x%x\n", __FILE__,
      |   ^~~~~~

Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Helge Deller <deller@gmx.de>