Older compilers don't support the -m4a{,nofpu} flags, which has the
side-effect of allowing FP operations to be emitted. Switch this to
incremental tuning, so we at least have -m4-nofpu as a fallback for
the gcc3 toolchains.

Without this, certain modules emit references to __udivsi3_i4 and
__sdivsi3_i4.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>