gpib: cb7210: Fix region leak when request_irq fails

When request_irq() fails, the region allocated by request_region()
is not released. Fix this by adding an error handling path with
proper goto labels to release the region.

Fixes: e9dc69956d4d ("staging: gpib: Add Computer Boards GPIB driver")
Closes: https://lore.kernel.org/oe-kbuild-all/202605160620.ReBOadPX-lkp@intel.com/
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260518022939.16881-1-zenghongling@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>