led_display: split led display support into generic and hw-dependent parts

Split the display command into generic interface and hardware-specific
realization for PDSP188x LED display found on hmi1001 and manroland
boards. Simple interface for LED displays is defined in
include/led-display.h and described in doc/README.LED_display.
Driver-specific implementation was moved into drivers/misc/pdsp188x.c
file (enabled with CONFIG_PDSP188x set).

Signed-off-by: Ilya Yanok <yanok@emcraft.com>
diff --git a/include/configs/hmi1001.h b/include/configs/hmi1001.h
index d40b7a9..8b0b773 100644
--- a/include/configs/hmi1001.h
+++ b/include/configs/hmi1001.h
@@ -352,6 +352,7 @@
 /* Display addresses						       */
 /*---------------------------------------------------------------------*/
 
+#define CONFIG_PDSP188x
 #define CONFIG_SYS_DISP_CHR_RAM	(CONFIG_SYS_DISPLAY_BASE + 0x38)
 #define CONFIG_SYS_DISP_CWORD		(CONFIG_SYS_DISPLAY_BASE + 0x30)
 
diff --git a/include/configs/manroland/common.h b/include/configs/manroland/common.h
index 0224608..291b669 100644
--- a/include/configs/manroland/common.h
+++ b/include/configs/manroland/common.h
@@ -55,6 +55,11 @@
 #define CONFIG_CMD_MII
 #define CONFIG_CMD_SNTP
 
+/*
+ * 8-symbol LED display (can be accessed with 'display' command)
+ */
+#define CONFIG_PDSP188x
+
 #define	CONFIG_TIMESTAMP	1	/* Print image info with timestamp */
 
 /*