regulator: bd70528: Remove .set_ramp_delay for bd70528_ldo_ops

The .set_ramp_delay should be for bd70528_buck_ops only.
Setting .set_ramp_delay for for bd70528_ldo_ops causes problem because
BD70528_MASK_BUCK_RAMP (0x10) overlaps with BD70528_MASK_LDO_VOLT (0x1f).
So setting ramp_delay for LDOs may change the voltage output, fix it.

Fixes: 99ea37bd

 ("regulator: bd70528: Support ROHM BD70528 regulator block")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20200101022406.15176-1-axel.lin@ingics.com
Signed-off-by: Mark Brown <broonie@kernel.org>