soc/intel/common/cse: Reorganize firmware update checks for CSE Lite

`cse_fw_update()` is currently checking whether an update is required
by comparing versions once and then again comparing versions later in
`cse_is_downgrade_instance()` to determine if the update is an upgrade
or downgrade. Additionally, if CSE RW partition is corrupt (determined
based on `cse_is_rw_bp_sign_valid()`), `cse_is_downgrade_instance()`
ends up using the corrupted version information to determine if it is
a downgrade instance.

This change reorganizes the firmware update checks to return different
status values:
1. CSE_UPDATE_NOT_REQUIRED: No update required. Versions match.
2. CSE_UPDATE_UPGRADE: Update required and it is an upgrade.
3. CSE_UPDATE_DOWNGRADE: Update required and it is a
downgrade (requires data clear).
4. CSE_UPDATE_CORRUPTED: `cse_is_rw_bp_sign_valid()` failed and hence
requires data clear.
5. CSE_UPDATE_METADATA_ERROR: Unable to read CSE metadata from CBFS.

This change also prepares the file for follow up changes which
completely drop cse_rw_metadata structure.

BUG=b:184892226

Change-Id: Iabecab8e373e65a11ba7fe1bfc125467571a0588
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58157
Reviewed-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions