m68k: Fix `struct sigcontext' for ColdFire
LibSegFault uses piggybacks sc_fpstate field of the `struct sigcontext'
and this patch avoids LibSegFault overflowing this field. Also this
removes an unnecessary divergence from classic m68k.
Signed-off-by: Maxim Kuvyrkov <maxim@codesourcery.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>