ASoC: fsl-asoc-card: set priv->pdev before using it

In the Linux kernel, the following vulnerability has been resolved: ASoC: fsl-asoc-card: set priv->pdev before using it priv->pdev pointer was set after being used in fsl_asoc_card_audmux_init(). Move this assignment at the start of the probe function, so sub-functions can correctly use pdev through priv. fsl_asoc_card_audmux_init() dereferences priv->pdev to get access to the dev struct, used with dev_err macros. As priv is zero-initialised, there would be a NULL pointer dereference. Note that if priv->dev is dereferenced before assignment but never used, for example if there is no error to be printed, the driver won't crash probably due to compiler optimisations.