arm64: dts: Fix leftover entry-methods for PSCI

arm64: dts: Fix leftover entry-methods for PSCI

These two device trees were either missed or added after
the commit correcting the "entry-method" from
"arm,psci" to just "psci" as per the binding.

Link: https://lore.kernel.org/r/20200322115846.16265-1-linus.walleij@linaro.org
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>