staging: hisilicon,hisi-spmi-controller.yaml cleanup schema

Remove some properties already defined at SPMI bus, and
place the type for the spmi-channel.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/4e4a80d3a1b84a354d3c40be374a1689ae6c0fb1.1616695231.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>