arm64: dts: meson: fixup SCP sram nodes

The GX and AXG SCP sram nodes were using invalid compatible and
node names for the sram entries.

Fixup the sram entries node names, and use proper compatible for them.

It notably fixes:
sram@c8000000: 'scp-shmem@0', 'scp-shmem@200' do not match any of the regexes: '^([a-z]*-)?sram(-section)?@[a-f0-9]+$', 'pinctrl-[0-9]+'

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200326165958.19274-3-narmstrong@baylibre.com