staging: hi6421-spmi-pmic: cleanup some macros

Before moving this driver out of staging, cleanup the macros,
in order to make the driver clearer.

No functional changes.

Suggested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/95341999de15b395242b5b7850ec5e727420ce19.1624606660.git.mchehab+huawei@kernel.org


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