sh: Do not define -ffreestanding twice
-ffreestanding is defined at the top Makefile for all architectures.
Do not define it twice for SH2A.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>