iwlwifi: avoid access out of memory allocated

The value in num_lmac can be bigger than mem_cfg->lmac array,
warn in case it's bigger.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Fixes: 68025d5f ("iwlwifi: dbg: refactor dump code to improve readability")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>