m68k: fpsp040: Remove meaningless $(OS_OBJS)

'git grep OS_OBJS' hits only this line. $(OS_OBJS) is just empty.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210331144336.25628-1-masahiroy@kernel.org


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>