disk: Use Makefile to omit partition drivers

At present these files have an #ifdef covering the whole file. Move the
condition to the Makefile instead.

Add BLK to the condition since future patches will adjust things so that
HAVE_BLOCK_DEVICE is only for SPL, but the partition drivers are needed
in U-Boot proper too.

Signed-off-by: Simon Glass <sjg@chromium.org>
7 files changed