wifi: ath12k: add EHT rate handling to existing set rate functions

wifi: ath12k: add EHT rate handling to existing set rate functions

Add EHT rate handling to the existing rate functions that validate,
prepare and set rates.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1

Co-developed-by: Aloka Dixit <aloka.dixit@oss.qualcomm.com>
Signed-off-by: Aloka Dixit <aloka.dixit@oss.qualcomm.com>
Signed-off-by: Muna Sinada <muna.sinada@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20251024001928.257356-3-muna.sinada@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>