clocks: sdm845: Import qcom,gcc-sdm845.h

Rather than using magic numbers as clock ids for peripherals import
qcom,gcc-sdm845.h from Linux to be used standard macros for clock ids.
So start using corresponding clk-id macro for debug UART.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>