iwlwifi: dbg: add infra for tracking free buffer size

Until now function just got a pointer to some buffer and used it as if
it's good to use with no boundaries about size left in the buffer.

This infra helps for internal functions ops to make sure buffer usage
is in bound of allocation.

We also add external checks with warnings to verify every internal
function didn't exceed usage of the free buffer size.
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220129105618.25c90fb14968.Ic8f05581a745d08011ca29b3f42767402643e8c5@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>