This framework only manages enabling and disabling regulators.
Peripheral drivers have to register their regulator with
stm32mp_regulator_register function, which calls plat_get_regulator.
This function has to be defined at platform level, to bind the
regulator ops depending on the regulator ID.
The functions stm32mp_regulator_enable and stm32mp_regulator_disable
can then be called inside drivers to manage their regulators.

Change-Id: I981bc6083015b0e1c307a5a9559573b80f81fc69
Signed-off-by: Yann Gautier <yann.gautier@st.com>
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/132817


Tested-by: Lionel DEBIEVE <lionel.debieve@st.com>
Reviewed-by: Lionel DEBIEVE <lionel.debieve@st.com>
Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: CIBUILD <smet-aci-builds@lists.codex.cro.st.com>