arm64: dts: sprd: sc9860: Simplify clock nodes

arm64: dts: sprd: sc9860: Simplify clock nodes

The various "syscon" nodes in SC9860 are only referenced by clock
provider nodes in a 1:1 relationship, and nothing else references the
"syscon" nodes. There's no apparent reason for this split. The 2 nodes
can simply be merged into 1 node. The clock driver has supported using
either "reg" or "sprd,syscon" to access registers from the start, so
there shouldn't be any compatibility issues.

With this, DT schema warnings for missing a specific compatible with
"syscon" and non-MMIO devices on "simple-bus" are fixed.

Reviewed-by: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20251124210031.767382-2-robh@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>