board/freescale/common: VSC3316/VSC3308 initialization code

Add code for configuring VSC3316/3308 crosspoint switches
Add README to understand the APIs

   - VSC 3316/3308 is a low-power, low-cost asynchronous crosspoint switch
     capable of data rates upto 11.5Gbps. VSC3316 has 16 input and 16
     output ports whereas VSC3308 has 8 input and 8 output ports.
     Programming of these devices are performed by two-wire or four-wire
     serial interface.

Signed-off-by: Shaveta Leekha <shaveta@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/board/freescale/common/Makefile b/board/freescale/common/Makefile
index 54cb098..36f7c4f 100644
--- a/board/freescale/common/Makefile
+++ b/board/freescale/common/Makefile
@@ -53,6 +53,7 @@
 COBJS-$(CONFIG_P3041DS)		+= ics307_clk.o
 COBJS-$(CONFIG_P4080DS)		+= ics307_clk.o
 COBJS-$(CONFIG_P5020DS)		+= ics307_clk.o
+COBJS-$(CONFIG_VSC_CROSSBAR)    += vsc3316_3308.o
 
 # deal with common files for P-series corenet based devices
 SUBLIB-$(CONFIG_P2041RDB)	+= p_corenet/libp_corenet.o