arm64: dts: amlogic: meson-gx: add the Mali-450 OPP table and use DVFS

Add the OPP table for the Mali-450 GPU and drop the hardcoded initial
clock configuration. This enables GPU DVFS and thus saves power when the
GPU is not in use while still being able switch to a higher clock on
demand.

Set the GP0_PLL clock to 744MHz (which is the only frequency which
cannot be derived from the FCLK dividers) as the clock driver avoids
setting the parent clock rates so the MPLL clocks aren't changed (as
these are reserved for audio). The only exception to this is the GXL
S805X package because the 744MHz OPP isn't working correctly there.

While here, make most of meson-gxl-mali re-usable to reduce the amount
of duplicate code between GXBB and GXL. This is more important now as we
don't want to duplicate the GPU OPP table.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200719173213.639540-2-martin.blumenstingl@googlemail.com

ARM64: dts: meson-gxl: fix Mali GPU compatible string

meson-gxl-mali.dtsi is only used on GXL SoCs. Thus it should use the GXL
specific compatible string instead of the GXBB one.
For now this is purely cosmetic since the (out-of-tree) lima driver for
this GPU currently uses the "arm,mali-450" match instead of the SoC
specific one. However, update the .dts to match the documentation since
this driver behavior might change in the future.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

ARM64: dts: meson: bump mali450 clk to 744MHz

The Mali-450 IP can run up to 744MHz, bump the frequency using
the GP0 PLL clock.

Cc: Michal Lazo <michal.lazo@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

ARM64: dts: amlogic: Convert to new-style SPDX license identifiers

Move the SPDX-License-Identifier lines to the top and drop the
license splat.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

ARM64: dts: meson-gx: Add Mali nodes for GXBB and GXL

The same Mali-450 MP3 GPU is present in the GXBB and GXL SoCs.

The node is simply added in the meson-gxbb.dtsi file.

For GXL, since a lot is shared with the GXM that has a Mali-T820 IP, this
patch adds a new meson-gxl-mali.dtsi and is included in the SoC specific
dtsi files.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[khilman: s/MALI/Mali in changelog]
Signed-off-by: Kevin Hilman <khilman@baylibre.com>