refactor(auth): separate bl1 and bl2 CoT

Separate the bl1 and bl2 CoT into individual C files for the
upcoming tool, i.e. the CoT device tree-to-source file generator.

Change-Id: I0d24791991b3539c7aef9a562920dc62fecdc69a
Signed-off-by: Xialin Liu <Xialin.Liu@ARM.com>
diff --git a/plat/arm/common/arm_common.mk b/plat/arm/common/arm_common.mk
index 2c1888d..0b6b526 100644
--- a/plat/arm/common/arm_common.mk
+++ b/plat/arm/common/arm_common.mk
@@ -384,18 +384,18 @@
             endif
         endif
     else ifeq (${COT},dualroot)
-        BL1_SOURCES	+=	drivers/auth/dualroot/cot.c
+        BL1_SOURCES	+=	drivers/auth/dualroot/bl1_cot.c
         ifneq (${COT_DESC_IN_DTB},0)
             BL2_SOURCES	+=	lib/fconf/fconf_cot_getter.c
         else
-            BL2_SOURCES	+=	drivers/auth/dualroot/cot.c
+            BL2_SOURCES	+=	drivers/auth/dualroot/bl2_cot.c
         endif
     else ifeq (${COT},cca)
-        BL1_SOURCES	+=	drivers/auth/cca/cot.c
+        BL1_SOURCES	+=	drivers/auth/cca/bl1_cot.c
         ifneq (${COT_DESC_IN_DTB},0)
             BL2_SOURCES	+=	lib/fconf/fconf_cot_getter.c
         else
-            BL2_SOURCES	+=	drivers/auth/cca/cot.c
+            BL2_SOURCES	+=	drivers/auth/cca/bl2_cot.c
         endif
     else
         $(error Unknown chain of trust ${COT})