Fix the build error for dualroot chain of trust.

Fixed build error for dualroot chain of trust.
Build error were thrown as below while compiling the code for
dualroot chain of trust:

aarch64-none-elf-ld.bfd: ./build/fvp/debug/bl1/tbbr_cot_bl1.o:
(.bss.auth_img_flags+0x0): multiple definition of `auth_img_flags';
./build/fvp/debug/bl1/cot.o:(.bss.auth_img_flags+0x0): first defined here

aarch64-none-elf-ld.bfd: ./build/fvp/debug/bl1/tbbr_cot_bl1.o:
(.rodata.cot_desc_size+0x0): multiple definition of `cot_desc_size';
./build/fvp/debug/bl1/cot.o:(.rodata.cot_desc_size+0x0): first defined here

aarch64-none-elf-ld.bfd: ./build/fvp/debug/bl1/tbbr_cot_bl1.o:
(.rodata.cot_desc_ptr+0x0): multiple definition of `cot_desc_ptr';
./build/fvp/debug/bl1/cot.o:(.rodata.cot_desc_ptr+0x0): first defined here
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I1a426c4e7f5f8013d71dafc176c7467c1b329757

plat/arm/common/arm_common.mk

@@ -298,6 +298,8 @@ ifneq (${TRUSTED_BOARD_BOOT},0)
     # Include the selected chain of trust sources.
     ifeq (${COT},tbbr)
         AUTH_SOURCES	+=	drivers/auth/tbbr/tbbr_cot_common.c
+	BL1_SOURCES     +=      drivers/auth/tbbr/tbbr_cot_bl1.c
+	BL2_SOURCES     +=      drivers/auth/tbbr/tbbr_cot_bl2.c
     else ifeq (${COT},dualroot)
         AUTH_SOURCES	+=	drivers/auth/dualroot/cot.c
     else
@@ -307,12 +309,10 @@ ifneq (${TRUSTED_BOARD_BOOT},0)
     BL1_SOURCES		+=	${AUTH_SOURCES}					\
 				bl1/tbbr/tbbr_img_desc.c			\
 				plat/arm/common/arm_bl1_fwu.c			\
-				drivers/auth/tbbr/tbbr_cot_bl1.c		\
 				plat/common/tbbr/plat_tbbr.c
 
     BL2_SOURCES		+=	${AUTH_SOURCES}					\
-				plat/common/tbbr/plat_tbbr.c			\
-				drivers/auth/tbbr/tbbr_cot_bl2.c
+				plat/common/tbbr/plat_tbbr.c
 
     $(eval $(call TOOL_ADD_IMG,ns_bl2u,--fwu,FWU_))