ASoC: fsl_xcvr: fix potential resource leak

"fw" variable must be relased before return.

Signed-off-by: Viorel Suman <viorel.suman@nxp.com>
Link: https://lore.kernel.org/r/20201124141957.20481-1-viorel.suman@oss.nxp.com


Signed-off-by: Mark Brown <broonie@kernel.org>