ice: Rename a couple of variables

[ Upstream commit 0be39bb4

 ]

In ice_set_link_ksettings, change 'abilities' to 'phy_caps' and 'p' to
'pi'. This is more consistent with similar usages elsewhere in the
driver.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>