ath11k: change fw build id format in driver init log

Currently fw build id is printed during init as follows.

fw_version 0x250684a5 fw_build_timestamp 2021-07-13 10:57
fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HK.2.5.0.1-01100-QCAHKSWPL_SILICONZ-1

The string "QC_IMAGE_VERSION_STRING=" is removed from the log
to improve readability.

With this patch the fw build id is printed during init as follows.
fw_version 0x250684a5 fw_build_timestamp 2021-07-13 10:57
fw_build_id WLAN.HK.2.5.0.1-01100-QCAHKSWPL_SILICONZ-1

Signed-off-by: Hari Chandrakanthan <quic_haric@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1646825065-7736-1-git-send-email-quic_haric@quicinc.com