SPL: Add YMODEM over UART load support

Adds support for loading U-Boot from UART using YMODEM protocol.
If YMODEM support is enabled in SPL and the romcode indicates
that SPL loaded via UART then SPL will wait for start of a
YMODEM transfer via the console port.

Signed-off-by: Matt Porter <mporter@ti.com>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/common/Makefile b/common/Makefile
index fd9b3b0..04faa0b 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -185,6 +185,9 @@
 COBJS-$(CONFIG_USB_KEYBOARD) += usb_kbd.o
 endif
 
+ifdef CONFIG_SPL_BUILD
+COBJS-$(CONFIG_SPL_YMODEM_SUPPORT) += xyzModem.o
+endif
 COBJS-y += console.o
 COBJS-y += dlmalloc.o
 COBJS-y += memsize.o