ARM: dts: aspeed: romed8hm3: Fix GPIOB0 name

This GPIO was mislabeled as DDR_MEM_TEMP in the schematic; after a
correction from ASRock Rack its name now reflects its actual
functionality (POST_COMPLETE_N).

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Fixes: a9a3d60b ("ARM: dts: aspeed: Add ASRock ROMED8HM3 BMC")
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20220331022425.28606-2-zev@bewilderbeest.net


Signed-off-by: Joel Stanley <joel@jms.id.au>