feat(plat/rcar3): add optional support for gzip-compressed BL33

The BL33 size on this platform is limited to 1 MiB, add optional
support for decompressing and starting gzip-compressed BL33, which
may help with this size limitation. This functionality is disabled
by default, set RCAR_GEN3_BL33_GZIP=1 during build to enable it.

The BL33 at 0x50000000 should then be gzip compressed, however if
the BL33 does not have a valid gzip header, it is copied to the
correct location and started as-is, this is a fallback for legacy
systems and systems which update to gzip-compressed BL33.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: Id93f1c7e6f17db1ffb952ea086562993473f6efa
3 files changed