arm64: dts: apm: Use lowercase consistently for hex constants

The convention in these files is to use lowercase for "0x" prefixes and for
the hex constants themselves, but a few changes didn't follow that
convention, which makes the file annoying to read.

Use lowercase consistently for the hex constants.  No functional change
intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Duc Dang <dhdang@apm.com>