malta: Use device model & tree for UART

Make use of device model & device tree to probe the UART driver. This is
the initial step in bringing Malta up to date with driver model, and
allows for cleaner handling of the different I/O addresses for different
system controllers by specifying the ISA bus address instead of a
translated memory address.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index dc34c18..53363e3 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -23,7 +23,11 @@
 
 config TARGET_MALTA
 	bool "Support malta"
+	select DM
+	select DM_SERIAL
 	select DYNAMIC_IO_PORT_BASE
+	select OF_CONTROL
+	select OF_ISA_BUS
 	select SUPPORTS_BIG_ENDIAN
 	select SUPPORTS_LITTLE_ENDIAN
 	select SUPPORTS_CPU_MIPS32_R1