PCI: Remove exclusive requests flags from _pcim_request_region()

PCI: Remove exclusive requests flags from _pcim_request_region()

pcim_request_region_exclusive(), the only user in PCI devres that needed
exclusive region requests, has been removed.

All features related to exclusive requests can, therefore, be removed,
too. Remove them.

Signed-off-by: Philipp Stanner <phasta@kernel.org>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250519112959.25487-6-phasta@kernel.org