chore(arm): remove duplicate defines

Change-Id: I9eea1610660bfa92f7781deab60e29eae11c4ba6
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
diff --git a/plat/arm/common/arm_common.mk b/plat/arm/common/arm_common.mk
index dff0135..74ba77d 100644
--- a/plat/arm/common/arm_common.mk
+++ b/plat/arm/common/arm_common.mk
@@ -433,10 +433,6 @@
     $(info Including ${MEASURED_BOOT_MK})
     include ${MEASURED_BOOT_MK}
 
-    ifneq (${MBOOT_EL_HASH_ALG}, sha256)
-        $(eval $(call add_define,TF_MBEDTLS_MBOOT_USE_SHA512))
-    endif
-
     ifeq (${MEASURED_BOOT},1)
          BL1_SOURCES		+= 	${EVENT_LOG_SOURCES}
          BL2_SOURCES		+= 	${EVENT_LOG_SOURCES}