sh: sh4: Remove CONFIG_SH4A definition from source code

SH4 and SH4A are compatible. But some instructions are different from these.
In Linux kernel, It is treated as a separate CPU, but for now, I think that
there is no need to divide especially in the U-Boot.

This removes CONFIG_SH4A definition from source code, SH4A is treated as SH4.
And this fix white space.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>