ARM64: dts: vexpress: Use a symlink to vexpress-v2m-rs1.dtsi from arch=arm

ARM64: dts: vexpress: Use a symlink to vexpress-v2m-rs1.dtsi from arch=arm

Commit 9ccd608070b6 "arm64: dts: add device tree for ARM SMM-A53x2 on
LogicTile Express 20MG" added a new dts file to arch/arm64 which
included "../../../../arm/boot/dts/vexpress-v2m-rs1.dtsi", i.e. a
.dtsi supplied by arch/arm.

Unfortunately this causes some issues for the split device tree
repository[0], since things get moved around there. In that context
the new .dts ends up at src/arm64/arm/vexpress-v2f-1xv7-ca53x2.dts
while the include is at src/arm/vexpress-v2m-rs1.dtsi.

The sharing of the .dtsi is legitimate since the baseboard is the same
for various vexpress systems whatever processor they use.

Previously I attempted to resolve this by creating a shared location
for such things but we have been unable to come to a consensus on
where that should be.

Instead this patch simply replaces the use of ../../ in the dts
/include/ with a symlink in arch/arm64/boot/dts/arm pointing to the
file arch/arm/boot/dts.

Since the split device tree repo will shortly be required to flatten
symlinks for other reasons this will cause the dtsi file to appear in
both src/arm and src/arm64 in the split repo, which is an improvement
on not building for arm64 now.

[0] https://git.kernel.org/cgit/linux/kernel/git/devicetree/devicetree-rebasing.git/

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Kristina Martsenko <kristina.martsenko@arm.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Frank Rowand <frank.rowand@sonymobile.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: arm@kernel.org
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>