net: atlantic: correct L3L4 filter flow_type masking and IPv6 handling

net: atlantic: correct L3L4 filter flow_type masking and IPv6 handling

Correct three issues in aq_set_data_fl3l4() required for the AQC113
PTP filter path introduced later in this series:

1. Mask FLOW_EXT from flow_type before the protocol switch statement.
   Flow types with FLOW_EXT set (e.g. TCP_V4_FLOW | FLOW_EXT) fall
   through to the default case and skip protocol comparison flags.

2. Extend the L3 address comparison check to cover all four IPv6
   words. The original code only checked ip_src[0]/ip_dst[0] and
   required !is_ipv6, so CMP_SRC_ADDR_L3/CMP_DEST_ADDR_L3 were never
   set for IPv6 filters.

3. Use explicit flow type checks for port extraction instead of
   negating IP_USER_FLOW/IPV6_USER_FLOW. The old check did not mask
   FLOW_EXT, so IP_USER_FLOW | FLOW_EXT would incorrectly attempt
   port extraction. Use the actual flow type to pick the correct
   union member directly.

Signed-off-by: Sukhdeep Singh <sukhdeeps@marvell.com>
Link: https://patch.msgid.link/20260610115448.272-2-sukhdeeps@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>