ARM: debug: qcom: add UART addresses to Kconfig help for APQ8084

Add information about the APQ8084 debug UART physical and virtual
addresses in the DEBUG_QCOM_UARTDM Kconfig help section.

Signed-off-by: Georgi Djakov <gdjakov@mm-sol.com>
Signed-off-by: Kumar Gala <galak@codeaurora.org>