arm64: dts: arm: align watchdog and mmc node names with dtschema

Align the watchdog and mmc device node names with the schema to fix
warnings like:

  mmci@50000: $nodename:0: 'mmci@50000' does not match '^mmc(@.*)?$'
  wdt@f0000: $nodename:0: 'wdt@f0000' does not match '^watchdog(@.*|-[0-9a-f])?$'

Link: https://lore.kernel.org/r/20210820081733.83976-1-krzysztof.kozlowski@canonical.com


Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>