power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors

power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors

This driver is used to control the PCIe M.2 connectors of different
Mechanical Keys attached to the host machines and supporting different
interfaces like PCIe/SATA, USB/UART etc...

Currently, this driver supports only the Mechanical Key M connectors with
PCIe interface. The driver also only supports driving the mandatory 3.3v
and optional 1.8v power supplies. The optional signals of the Key M
connectors are not currently supported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260122-pci-m2-v6-4-575da9f97239@oss.qualcomm.com
[Bartosz: rename pwrseq_pcie_m2_free_resources() to pwrseq_pcie_m2_free_regulators()]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>