MMC devices support multiple partitions, defined by the hardware. At
present U-Boot can only access partition zero. Add support for selecting
other partitions.

Also add a way to check if a partition is write-protected.

Note: There is existing support for this in the legacy MMC code, but this
is being removed soon.

Series-to: u-boot
Process-logs: sort, uniq
Series-version: 2
Series-changes: 2
- Drop changes previously applied
- Drop patch 'efi_loader: Don't enable in SPL/TPL by default'

Cover-letter:
sandbox: Changes and improvements to support verified boot
This series compiles a number of fixes and improvement sto sandbox,
cros_ec, tpm and a few other pieces. This allows U-Boot to support
Chromium OS verified boot and assist with debugging of this.
END

Change-Id: I44025b99f36aedf749158db6d9edbb187b3c5c35
Signed-off-by: Simon Glass <sjg@chromium.org>