The process_eap_data function was dereferencing data->data before
checking if the pointers were NULL, which could lead to segmentation
faults.

This commit moves the null checks to the beginning of the function
and returns early if null pointers are detected, preventing the
dereference from occurring.

Changes:
- Add null check for data and data->data at function start
- Return early with error logging if NULL
- Remove redundant null checks before free() calls