wcn36xx: Correct DXE chip version differentiation

The CCU block in WCNSS is configured for appropriate routing of
interrupts from the DXE to the application cpu, this is not dependant on
the iris version (wcn3660 vs wcn3680), but rather if the SoC has a riva
or pronto built in.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>