Blackfin: add an early shadow console

Add a memory based shadow console to keep a copy of the printk buffer in a
location which can be found externally.  This allows bootloaders to locate
and utilize the log buffer in case of silent (early/resume/etc...) crashes.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/kernel/setup.c b/arch/blackfin/kernel/setup.c
index 6dbf219..3974764 100644
--- a/arch/blackfin/kernel/setup.c
+++ b/arch/blackfin/kernel/setup.c
@@ -810,6 +810,8 @@
 {
 	unsigned long sclk, cclk;
 
+	enable_shadow_console();
+
 	/* Check to make sure we are running on the right processor */
 	if (unlikely(CPUID != bfin_cpuid()))
 		printk(KERN_ERR "ERROR: Not running on ADSP-%s: unknown CPUID 0x%04x Rev 0.%d\n",