staging: gpib: cb7210: Handle gpib_register_driver() errors

staging: gpib: cb7210: Handle gpib_register_driver() errors

The function cb_pcmcia_init_module() can be replaced by calling
pcmcia_register_driver() directly. The error value from this
function is not returned and the previous registering functions
are not unregistered.

The function gpib_register_driver() can fail and similar to
pcmcia_register_driver() function failing, the previous registering
functions are not unregistered.

Replace cb_pcmcia_init_module() with pcmcia_register_driver().
Unregister the gpib and pci register functions if the subsequent
gpib or pcmcia register functions fail and return the error value.
Add pr_err() statements to indicate the fail and also the error
value.

Signed-off-by: Nihar Chaithanya <niharchaithanya@gmail.com>
Link: https://lore.kernel.org/r/20241230185633.175690-5-niharchaithanya@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>