mtd: rawnand: Use non-hybrid PCI devres API

denali_pci.c enables a PCI device with pcim_enable_device(). This,
implicitly, switches the function pci_request_regions() into managed
mode, where it becomes a devres function.

The PCI subsystem wants to remove this hybrid nature from its
interfaces. To do so, users of the aforementioned combination of
functions must be ported to non-hybrid functions.

Moreover, since both functions are already managed in this driver, the
calls to pci_release_regions() are unnecessary.

Remove the calls to pci_release_regions().

Replace the call to sometimes-managed pci_request_regions() with one to
the always-managed pcim_request_regions().

Signed-off-by: Philipp Stanner <phasta@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>