powerpc: Fix SPE Power ISA properties for e500v1 platforms

Commit 2eb28006431c ("powerpc/e500v2: Add Power ISA properties to comply
with ePAPR 1.1") introduced new include file e500v2_power_isa.dtsi and
should have used it for all e500v2 platforms. But apparently it was used
also for e500v1 platforms mpc8540, mpc8541, mpc8555 and mpc8560.

e500v1 cores compared to e500v2 do not support double precision floating
point SPE instructions. Hence power-isa-sp.fd should not be set on e500v1
platforms, which is in e500v2_power_isa.dtsi include file.

Fix this issue by introducing a new e500v1_power_isa.dtsi include file and
use it in all e500v1 device tree files.

Fixes: 2eb28006431c ("powerpc/e500v2: Add Power ISA properties to comply with ePAPR 1.1")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220902212103.22534-1-pali@kernel.org