kbuild: cherry-pick kbuild fdtoverlay changes from linux

kbuild: cherry-pick kbuild fdtoverlay changes from linux

Linux commits:
15d16d6dadf6 kbuild: Add generic rule to apply fdtoverlay
44f87191d105 kbuild: parameterize the .o part of suffix-search

The Linux commit 15d16d6dadf6 adds a generic rule in Makefile.lib
to automatically apply fdtoverlay, so that each platform doesn't
need to include a complex rule. This also automatically appends
DTC_FLAGS_foo_base += -@ to all base files

The platform's Makefile only needs to have this now:

foo-dtbs := foo_base.dtb foo_overlay1.dtbo foo_overlay2.dtbo
dtb-y := foo.dtb

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20240906070808.1045991-2-prasad.kummari@amd.com