Add mutex_destroy() call in driver initialization error flow.

Fixes: 6882b0ae ("mlxsw: Introduce support for I2C bus")
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20220407070703.2421076-1-idosch@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>