ath10k: bypass PLL setting on target init for QCA9888

Some of of qca988x solutions are having global reset issue
during target initialization. Bypassing PLL setting before
downloading firmware and letting the SoC run on REF_CLK is fixing
the problem. Corresponding firmware change is also needed to set
the clock source once the target is initialized. Since 10.2.4
firmware is having this ROM patch, applying skip_clock_init only
for 10.2.4 firmware versions.

Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>