fix(drivers/st/pmic): missing error check
fix(drivers/st/pmic): missing error check

In pmic_operate(), "regulators" node value must be checked before
entering in the fdt_for_each_subnode loop.

Change-Id: I1460cd24ec56ec47ab644f396b71b92973e75fb4
Signed-off-by: Nicolas Le Bayon <459e1b953d452717fc0922478c0f29e0cac09091@st.com>
Signed-off-by: Yann Gautier <e753f6969c288905606e3c07464886d4f1fc1be0@st.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware