Fully initialise essential control registers

This patch updates the el3_arch_init_common macro so that it fully
initialises essential control registers rather then relying on hardware
to set the reset values.

The context management functions are also updated to fully initialise
the appropriate control registers when initialising the non-secure and
secure context structures and when preparing to leave EL3 for a lower
EL.

This gives better alignement with the ARM ARM which states that software
must initialise RES0 and RES1 fields with 0 / 1.

This patch also corrects the following typos:

"NASCR definitions" -> "NSACR definitions"

Change-Id: Ia8940b8351dc27bc09e2138b011e249655041cfc
Signed-off-by: David Cunado <david.cunado@arm.com>
diff --git a/include/common/ep_info.h b/include/common/ep_info.h
index 23d27c4..3f6213f 100644
--- a/include/common/ep_info.h
+++ b/include/common/ep_info.h
@@ -33,6 +33,7 @@
 			((x) = ((x) & ~PARAM_EP_SECURITY_MASK) | (security))
 
 #define EP_EE_MASK	U(0x2)
+#define EP_EE_SHIFT	1
 #define EP_EE_LITTLE	U(0x0)
 #define EP_EE_BIG	U(0x2)
 #define EP_GET_EE(x) (x & EP_EE_MASK)