drm/msm/dsi: invalid parameter check in msm_dsi_phy_enable
In the Linux kernel, the following vulnerability has been resolved:

drm/msm/dsi: invalid parameter check in msm_dsi_phy_enable

The function performs a check on the "phy" input parameter, however, it
is used before the check.

Initialize the "dev" variable after the sanity check to avoid a possible
NULL pointer dereference.

Addresses-Coverity-ID: 1493860 ("Null pointer dereference")