idpf: remove obsolete stashing code

jira KERNEL-170
commit-author Joshua Hay <joshua.a.hay@intel.com>
commit 6c4e684
upstream-diff |
	- adjusted context due to missing idpf_tx_read_tstamp func;
	- adjusted the number of bytes expected in
	libeth_cacheline_set_assert for struct idpf_tx_queue due to missing
	of some elements in the struct;
	both are due to missing commit
	1a49cf8 ("idpf: add Tx timestamp flows").

With the new Tx buffer management scheme, there is no need for all of
the stashing mechanisms, the hash table, the reserve buffer stack, etc.
Remove all of that.

	Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
	Reviewed-by: Madhu Chittim <madhu.chittim@intel.com>
	Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
	Tested-by: Samuel Salin <Samuel.salin@intel.com>
	Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
(cherry picked from commit 6c4e684)
	Signed-off-by: Roxana Nicolescu <rnicolescu@ciq.com>

Author: jahay1