edid: Library of EDID decode and print

This implements a library for accessing EDID data from an LCD panel.
This is used to obtain information about the panel such as its
resolution and type.

This is a tidied-up version of the original code pulled from
https://github.com/ynezz/u-boot-edid.

The changes we made are:
 - removed bit fields in the struct;
 - removed endianness cases in the struct;
 - fixed some wrong definitions;
 - fixed to fit 80 columns;
 - fixed some code styles.

Signed-off-by: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

common/Makefile

@@ -188,6 +188,7 @@ COBJS-$(CONFIG_BOOTSTAGE) += bootstage.o
 COBJS-$(CONFIG_CONSOLE_MUX) += iomux.o
 COBJS-y += flash.o
 COBJS-$(CONFIG_CMD_KGDB) += kgdb.o kgdb_stubs.o
+COBJS-$(CONFIG_I2C_EDID) += edid.o
 COBJS-$(CONFIG_KALLSYMS) += kallsyms.o
 COBJS-$(CONFIG_LCD) += lcd.o
 COBJS-$(CONFIG_LYNXKDI) += lynxkdi.o