PCI: shpchp: Remove 'shpchp_debug' module parameter

PCI: shpchp: Remove 'shpchp_debug' module parameter

The "shpchp_debug" module parameter is used to enable debug logging.  The
generic ability to turn on/off debug prints dynamically covers this use
case already so there is no need for module specific debug handling.  The
ctrl_dbg() wrapper also uses a low-level pci_printk() despite always using
KERN_DEBUG level.

Remove "shpchp_debug" parameter and convert ctrl_dbg() to use pci_dbg().

From now on, shpchp can be debugged using the normal dynamic debugger by
setting CONFIG_DYNAMIC_DEBUG=y and then either adding to kernel cmdline:

  dyndbg="file drivers/pci/hotplug/shpchp* +p"

or using this command on a running kernel:

  echo 'file drivers/pci/hotplug/shpchp* +p' > /sys/kernel/debug/dynamic_debug/control

Link: https://lore.kernel.org/r/20250217095550.2789-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>