dm: stv0991: Move driver model CONFIGs to Kconfig

Remove driver model CONFIGs from the board config headers and use Kconfig
instead.

Signed-off-by: Simon Glass <sjg@chromium.org>

configs/stv0991_defconfig

@@ -3,3 +3,5 @@ CONFIG_ARM=y
 CONFIG_TARGET_STV0991=y
 CONFIG_SYS_MALLOC_F=y
 CONFIG_SYS_MALLOC_F_LEN=0x2000
+CONFIG_DM=y
+CONFIG_DM_SERIAL=y

include/configs/stv0991.h

@@ -29,19 +29,9 @@
 #define CONFIG_SYS_MAXARGS			16
 #define CONFIG_SYS_MALLOC_LEN			(CONFIG_ENV_SIZE + 16 * 1024)
 
-#define CONFIG_DM
 /* serial port (PL011) configuration */
 #define CONFIG_BAUDRATE				115200
-#ifdef CONFIG_DM
-#define CONFIG_DM_SERIAL
 #define CONFIG_PL01X_SERIAL
-#else
-#define CONFIG_SYS_SERIAL0                     0x80406000
-#define CONFIG_CONS_INDEX			0
-#define CONFIG_PL011_SERIAL
-#define CONFIG_PL01x_PORTS                     {(void *)CONFIG_SYS_SERIAL0}
-#define CONFIG_PL011_CLOCK                     (2700 * 1000)
-#endif
 
 /* user interface */
 #define CONFIG_SYS_PROMPT			"STV0991> "