ARM64: dts: marvell: armada37xx: Fix timer interrupt specifiers

Contrary to popular belief, PPIs connected to a GICv3 to not have
an affinity field similar to that of GICv2. That is consistent
with the fact that GICv3 is designed to accomodate thousands of
CPUs, and fitting them as a bitmap in a byte is... difficult.

Fixes: adbc3695

 ("arm64: dts: add the Marvell Armada 3700 family and
a development board")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>