staging: rtl8712: check for return value of _r8712_init_xmit_priv()

staging: rtl8712: check for return value of _r8712_init_xmit_priv()

The return value of _r8712_init_xmit_priv() is never checked and the driver
always continue execution as if all is well. This will cause problems
if, for example, buffers cannot be allocated and the driver continue and
use those buffers.

Check for return value of _r8712_init_xmit_priv() and return error (if any)
during probing.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Signed-off-by: Nam Cao <namcaov@gmail.com>
Link: https://lore.kernel.org/r/b550803561acf26af71f2377215c28b94435a644.1666688642.git.namcaov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>