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/drivers/misc/Makefile b/drivers/misc/Makefile
index 4f15db9..5d668f8 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -33,6 +33,7 @@
 COBJS-$(CONFIG_STATUS_LED) += status_led.o
 COBJS-$(CONFIG_TWL4030_LED) += twl4030_led.o
 COBJS-$(CONFIG_FSL_PMIC) += fsl_pmic.o
+COBJS-$(CONFIG_PDSP188x) += pdsp188x.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)