sh: math-emu: drop unused functions

Delete ieee_fpe_handler() since it is not used. After that is done,
delete denormal_to_double() since it is not used:

.../arch/sh/math-emu/math.c:505:12: error: 'ieee_fpe_handler' defined but not used [-Werror=unused-function]
  505 | static int ieee_fpe_handler(struct pt_regs *regs)

.../arch/sh/math-emu/math.c:477:13: error: 'denormal_to_double' defined but not used [-Werror=unused-function]
  477 | static void denormal_to_double(struct sh_fpu_soft_struct *fpu, int n)

Fixes: 7caf62de ("sh: remove unused do_fpu_error")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Takashi YOSHII <takasi-y@ops.dti.ne.jp>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rich Felker <dalias@libc.org>