regulator: stpmic1: Set a default ramp delay value

Set a default ramp delay value to the regulators with the worst
case value.

Signed-off-by: pascal paillet <p.paillet@st.com>
Link: https://lore.kernel.org/r/20191113161529.27739-1-p.paillet@st.com


Signed-off-by: Mark Brown <broonie@kernel.org>