ti: k3: common: Make UART number configurable

This allows to build for k3-based boards that use a different UART as
console, such as the IOT2050 which requires K3_USART=1.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Change-Id: I7171f86c3cabae2c575b8fbeecef839b48bd109b
diff --git a/plat/ti/k3/include/platform_def.h b/plat/ti/k3/include/platform_def.h
index 690c68e..98db626 100644
--- a/plat/ti/k3/include/platform_def.h
+++ b/plat/ti/k3/include/platform_def.h
@@ -91,7 +91,7 @@
 
 /* Platform default console definitions */
 #ifndef K3_USART_BASE
-#define K3_USART_BASE 0x02800000
+#define K3_USART_BASE			(0x02800000 + 0x10000 * K3_USART)
 #endif
 
 /* USART has a default size for address space */