MLK-16225: clk: imx8qm: Add fsl,lpcg_base_offset property

MLK-16225: clk: imx8qm: Add fsl,lpcg_base_offset property

Right now the imx8qm clock provider hardcodes physical addresses. In
virtualization scenarios the intermediate physical addresses visible
from a guest can be different. In theory a 1:1 mapping could be done but
that in xen it would overlap with hardcoded guest ram starting at
0x40000000.

Solve this by adding a property with a common offset for all lpcg
areas. This should be set in the guest dts.

In theory each lpcg block could be remapped with it's own offset but
that is not supported.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Ranjani Vaidyanathan <Ranjani.vaidyanathan@nxp.com>