arm64: dts: qcom: qcs6490-rb3gen2: Update regulator settings

arm64: dts: qcom: qcs6490-rb3gen2: Update regulator settings

Update min/max voltage settings for regulators below to align
with the HW specification
vreg_l3b_0p504
vreg_l6b_1p2
vreg_l11b_1p504
vreg_l14b_1p08
vreg_l16b_1p1
vreg_l17b_1p7
vreg_s1c_2p19
vreg_l8c_1p62
vreg_l9c_2p96
vreg_l12c_1p65.

While at it, remove RPMH regulator rails (listed below) as
these are not to be used on APPS, and any client accidently
voting on it can potentially cause issues.
vreg_s2b_0p876
vreg_s2c_0p752
vreg_s5c_0p752
vreg_s7c_0p752
vreg_s10c_0p752
vreg_l4b_0p752
vreg_l5b_0p752.

Signed-off-by: Rakesh Kota <rakesh.kota@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250919-b4-rb3gen2-update-regulator-v1-1-1ea9e70d01cb@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>