Initialise CPU contexts from entry_point_info

Consolidate all BL3-1 CPU context initialization for cold boot, PSCI
and SPDs into two functions:
*  The first uses entry_point_info to initialize the relevant
   cpu_context for first entry into a lower exception level on a CPU
*  The second populates the EL1 and EL2 system registers as needed
   from the cpu_context to ensure correct entry into the lower EL

This patch alters the way that BL3-1 determines which exception level
is used when first entering EL1 or EL2 during cold boot - this is now
fully determined by the SPSR value in the entry_point_info for BL3-3,
as set up by the platform code in BL2 (or otherwise provided to BL3-1).

In the situation that EL1 (or svc mode) is selected for a processor
that supports EL2, the context management code will now configure all
essential EL2 register state to ensure correct execution of EL1. This
allows the platform code to run non-secure EL1 payloads directly
without requiring a small EL2 stub or OS loader.

Change-Id: If9fbb2417e82d2226e47568203d5a369f39d3b0f
diff --git a/bl1/aarch64/bl1_arch_setup.c b/bl1/aarch64/bl1_arch_setup.c
index 5725bac..8ed45d9 100644
--- a/bl1/aarch64/bl1_arch_setup.c
+++ b/bl1/aarch64/bl1_arch_setup.c
@@ -46,11 +46,10 @@
 	isb();
 
 	/*
-	 * Enable HVCs, route FIQs to EL3, set the next EL to be AArch64, route
-	 * external abort and SError interrupts to EL3
+	 * Set the next EL to be AArch64, route external abort and SError
+	 * interrupts to EL3
 	 */
-	tmp_reg = SCR_RES1_BITS | SCR_RW_BIT | SCR_HCE_BIT | SCR_EA_BIT |
-		  SCR_FIQ_BIT;
+	tmp_reg = SCR_RES1_BITS | SCR_RW_BIT | SCR_EA_BIT;
 	write_scr(tmp_reg);
 
 	/*