Blackfin: add workaround for anomaly 05000171

DESCRIPTION:
The Boot ROM is executed at power up/reset and changes the value of the
SICA_IWR registers from their default reset value of 0xFFFF, but does not
restore them.

WORKAROUND:
User code should not rely on the default value of these registers.  Set
the desired values explicitly.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

cpu/blackfin/initcode.c

@@ -355,6 +355,10 @@ void initcode(ADI_BOOT_DATA *bootstruct)
 		bfrom_SysControl(actions, &memory_settings, NULL);
 #if ANOMALY_05000432
 		bfin_write_SIC_IWR1(-1);
+#endif
+#if ANOMALY_05000171
+		bfin_write_SICA_IWR0(-1);
+		bfin_write_SICA_IWR1(-1);
 #endif
 	} else {
 		serial_putc('G');