PCI: Remove pcim_request_region_exclusive()

PCI: Remove pcim_request_region_exclusive()

pcim_request_region_exclusive() was only needed for redirecting the
relatively exotic exclusive request functions in pci.c in case of them
operating in managed mode.

The managed nature has been removed from those functions and no one else
uses pcim_request_region_exclusive().

Remove pcim_request_region_exclusive().

Signed-off-by: Philipp Stanner <phasta@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/r/20250519112959.25487-5-phasta@kernel.org