sh: Use -m2a-nofpu only

Based on reading over the GCC manual, passing both -m2a and -m2a-nofpu
are redundant, as -m2a-nofpu will provide functional code for both.  As
-m2a-nofpu functions with more toolchains and does what is expected,
switch.

Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Tom Rini <trini@konsulko.com>