mcb: fix a double free bug in chameleon_parse_gdd()

mcb: fix a double free bug in chameleon_parse_gdd()

In chameleon_parse_gdd(), if mcb_device_register() fails, 'mdev'
would be released in mcb_device_register() via put_device().
Thus, goto 'err' label and free 'mdev' again causes a double free.
Just return if mcb_device_register() fails.

Fixes: 3764e82e5150 ("drivers: Introduce MEN Chameleon Bus")
Cc: stable <stable@kernel.org>
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Link: https://lore.kernel.org/r/6201d09e2975ae5789879f79a6de4c38de9edd4a.1741596225.git.jth@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>