tests: logging: log_api: Fix in mock backend

Mock backend is using 32 bytes for hexdump data and
only hexdumps with less data shall be compared against
expected one. Wrong operator was used and comparing
was performed only when hexdump size exceeded 32 bytes.
Spotted by Coverity CID 236015.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
1 file changed