net/mlx5: split flow validation to dedicated function

net/mlx5: split flow validation to dedicated function

In current implementation the validation logic reside in the same
function that calculates the size of the verbs spec and also create the
verbs spec.
This approach results in hard to maintain code which can't be shared.
also in current logic there is a use of parser entity that holds the
information between function calls. The main problem with this parser is
that it assumes the connection between different functions. For example
it assumes that the validation function was called and relevant values
were set.
This may result in an issue if and when we only call the validation
function, or call the apply function without the validation (Currently
according to RTE flow we must call validation before creating flow, but
if we want to change that to save time during flow creation, for example
the user validated some rule and just want to change the IP there is no
true reason the validate the rule again).

This commit address both of those issues by extracting the validation
logic into detected functions and remove the use of the parser object.
The side effect of those changes is that in some cases there will be a
need to traverse the item list again.

Signed-off-by: Ori Kam <orika@mellanox.com>
Acked-by: Yongseok Koh <yskoh@mellanox.com>