sparc: leon3: Add debug_uart support to LEON3 serial driver.

Signed-off-by: Francois Retief <fgretief@spaceteq.co.za>
diff --git a/configs/grsim_defconfig b/configs/grsim_defconfig
index a5ea7ab..d2f709f 100644
--- a/configs/grsim_defconfig
+++ b/configs/grsim_defconfig
@@ -14,3 +14,7 @@
 # CONFIG_CMD_NET is not set
 # CONFIG_CMD_NFS is not set
 CONFIG_SYS_AMBAPP_PRINT_ON_STARTUP=y
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_APBUART=y
+CONFIG_DEBUG_UART_BASE=0x80000100
+CONFIG_DEBUG_UART_CLOCK=40000000