ARM: dts: imx23/8: Rename apbh and apbx nodes

According to simple-bus.yaml, apbh and apbx are not valid bus names.

Rename them to apbh-bus and apbx-bus to fix the following dt-schema
warnings:

'apbh@80000000' does not match '^([a-z][a-z0-9\\-]+-bus|bus|localbus|soc|axi|ahb|apb)(@.+)?$'
'apbx@80040000' does not match '^([a-z][a-z0-9\\-]+-bus|bus|localbus|soc|axi|ahb|apb)(@.+)?$'

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>