staging: sm750fb: add missing pci_release_region on error and removal

staging: sm750fb: add missing pci_release_region on error and removal

hw_sm750_map() calls pci_request_region() but never releases the
region on error paths or in lynxfb_pci_remove(). This causes a
resource leak that prevents the PCI region from being mapped again
after driver removal or a failed probe. A TODO comment in the code
acknowledges this missing cleanup.

Restructure the error handling in hw_sm750_map() to properly release
the PCI region on ioremap failures, and add pci_release_region() to
lynxfb_pci_remove().

Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260216202038.1828-1-iprintercanon@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>