drivers: video: fix NULL dereference in mipid02_get_fmt

Category: Null pointer dereference (CWE-476)

Corrects the logic that validates the result of mipid04_get_format_desc().
Previously, the check was inverted, which could lead to a NULL pointer
dereference when accessing desc->pixelformat.

Fixes Coverity CID: 525183

Signed-off-by: sudarsan N <sudarsansamy2002@gmail.com>