wifi: ath11k: Allow ath11k to boot without caldata in ftm mode

Currently, if ath11k is unable to load the calibration data file it will
always exit. However the calibration data may not be present in factory
test mode, so update the logic to allow the driver to execute in FTM mode
even if downloading the calibration data fails.

Tested-on : IPQ8074 hw2.0 AHB WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1

Signed-off-by: Sowmiya Sree Elavalagan <quic_ssreeela@quicinc.com>
Signed-off-by: Raj Kumar Bhagat <quic_rajkbhag@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230517135934.16408-5-quic_rajkbhag@quicinc.com