bus: mhi: host: pci_generic: Add pm_runtime_forbid() in remove callback

bus: mhi: host: pci_generic: Add pm_runtime_forbid() in remove callback

Add pm_runtime_forbid() to balance the pm_runtime_allow() call made
during Mission Mode transition. Without this, the device remains in runtime
PM allowed state even after driver removal.

Fixes: 855a70c12021 ("bus: mhi: Add MHI PCI support for WWAN modems")
Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
[mani: moved pm_runtime_forbid() to the start of remove()]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260303-b4-async_power_on-v2-2-d3db81eb457d@oss.qualcomm.com