net: phy: dp83867: remove check of delay strap configuration

The check that intended to handle "rgmii" PHY mode differently to the
RGMII modes with internal delay never worked as intended:

- added in commit 2a10154a ("net: phy: dp83867: Add TI dp83867 phy"):
  logic error caused the condition to always evaluate to true
- changed in commit a46fa260 ("net: phy: dp83867: Fix warning check
  for setting the internal delay"): now the condition incorrectly
  evaluates to false for rgmii-txid
- removed in commit 2b892649 ("net: phy: dp83867: Set up RGMII TX
  delay")

Around the time of the removal, commit c11669a2 ("net: phy: dp83867:
Rework delay rgmii delay handling") started clearing the delay enable
flags in RGMIICTL. The change attempted to preserve the historical
behavior of not disabling internal delays with "rgmii" PHY mode and also
documented this in a comment, but due to a conflict between "Set up
RGMII TX delay" and "Rework delay rgmii delay handling", the behavior
dp83867_verify_rgmii_cfg() warned about (and that was also described in
a comment in dp83867_config_init()) disappeared in the following merge
of net into net-next in commit b4b12b0d
("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net"

).

While is doesn't appear that this breaking change was intentional, it
has been like this since 2019, and the new behavior to disable the delays
with "rgmii" PHY mode is generally desirable - in particular with MAC
drivers that have to fix up the delay mode, resulting in the PHY driver
not even seeing the same mode that was specified in the Device Tree.

Remove the obsolete check and comment.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://patch.msgid.link/8a286207cd11b460bb0dbd27931de3626b9d7575.1746612711.git.matthias.schiffer@ew.tq-group.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>