disk: don't compile in partition support for spl/tpl if not really necessary

We see some increase of spl code size due to partition support (disk/*)
while none of particular partition types (CONFIG_SPL_XXX_PARTITION) are
enabled.
With this patch applied, part.c is no longer included unless really
necessary.

In addition, fix errors in CI build revealed after this change is made.

Fixes: commit 88ca8e26 ("disk: Add an option for partitions in SPL")
Fixes: commit 17f8cda5 ("efi_loader: set partition GUID in device path
	for SIG_TYPE_GUID")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>