Blackfin: implement bootcount support

The default storage location for bootcount is EVT0.  This version uses
one 32bit value and combines the magic/count value in the upper/lower
16bits.  If there is demand for more, should be easy to do.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/cpu/Makefile b/arch/blackfin/cpu/Makefile
index 211b8d5..50c1eea 100644
--- a/arch/blackfin/cpu/Makefile
+++ b/arch/blackfin/cpu/Makefile
@@ -17,6 +17,7 @@
 CEXTRA   := initcode.o
 SEXTRA   := start.o
 SOBJS    := interrupt.o cache.o
+COBJS-$(CONFIG_BOOTCOUNT_LIMIT) += bootcount.o
 COBJS-y  += cpu.o
 COBJS-y  += interrupts.o
 COBJS-$(CONFIG_JTAG_CONSOLE) += jtag-console.o