Our last sync with the kernel was 5.1.

We are so out of sync now, that tracking the patches and backporting
them one by one makes little sense and it's going to take ages.

This is an attempt to sync up Makefiles to 6.1.
Unfortunately due to sheer amount of patches this is not easy to review,
but that's what we decided during a community call for the bump to 5.1,
so we are following the same guidelines here.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>a #rebased on -next

Backported from kernel
commit ba97df45581f ("kbuild: use assignment instead of define ... endef for filechk_* rules")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

Backport from kernel
commit 3a2429e1faf4 ("kbuild: change if_changed_rule for multi-line recipe")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

Backport from kernel
commit 392885ee82d3 ("kbuild: let fixdep directly write to .*.cmd files")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

Backport from kernel
commit afa974b77128 ("kbuild: add real-prereqs shorthand for $(filter-out FORCE,$^)")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

Backported from the linux kernel
commit e4aca4595005 ("kbuild: de-duplicate fixdep usage")

A lot of the kernels kbuild depend on that patch. Backport it and pull in
the 'rule_as_o_S'a rule as well. This might end up being unused but it
doesn't break anything and makes diffing the files easier.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

It is confusing to have both "$(PHASE_)" and "$(XPL_)" be used in our
Makefiles as part of the macros to determine when to do something in our
Makefiles based on what phase of the build we are in. For consistency,
bring this down to a single macro and use "$(PHASE_)" only.

Signed-off-by: Tom Rini <trini@konsulko.com>

Use PHASE_ as the symbol to select a particular XPL build. This means
that SPL_TPL_ is no-longer set.

Update the comment in bootstage to refer to this symbol, instead of
SPL_

Signed-off-by: Simon Glass <sjg@chromium.org>

Use XPL_ as the symbol to indicate an SPL build. This means that SPL_ is
no-longer set.

Signed-off-by: Simon Glass <sjg@chromium.org>

Complete this rename for all directories outside arch/ board/ drivers/
and include/

Use the new symbol to refer to any 'SPL' build, including TPL and VPL

Signed-off-by: Simon Glass <sjg@chromium.org>