gskill: Check for ret < 0 in gskill_read_profile_name()
gskill: Check for ret < 0 in gskill_read_profile_name()

This was only working before because we weren't actually returning the
profile size correctly. Fix that up as well.

cvuchener/libratbag,libratbag/libratbag,cvuchener/libratbag,cvuchener/libratbag,libratbag/libratbag,libratbag/libratbag,whot/libratbag,whot/libratbag,whot/libratbag