scsi: ufs: core: Add support for TX Equalization

scsi: ufs: core: Add support for TX Equalization

MIPI Unipro3.0 introduced PA_TxEQGnSetting and PA_PreCodeEn attributes for
TX Equalization and Pre-Coding. It is Host Software's responsibility to
configure these attributes for both host and device before initiating Power
Mode Change to High-Speed Gears.

MIPI Unipro3.0 also introduced TX Equalization Training (EQTR) to identify
optimal TX Equalization settings for use by both Host's and Device's
UniPro. TX EQTR shall be initiated from the most reliable High-Speed Gear
(HS-G1) targeting High-Speed Gears (HS-G4 to HS-G6).

Implement TX Equalization configuration and TX EQTR procedure as defined
in UFSHCI v5.0 specification. The TX EQTR procedure determines the optimal
TX Equalization settings by iterating through all possible PreShoot and
DeEmphasis combinations and selecting the best combinations for both Host
and Device based on Figure of Merit (FOM) evaluation.

Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Link: https://patch.msgid.link/20260325152154.1604082-5-can.guo@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>