chore(measured boot): remove unused DTC flags

We no longer need to pass special flags to the device tree compiler
for measured boot. These are a left over from the days where we used
to pass BL2 measurement to BL2 image via TB_FW configuration file.

This should have been removed as part of commit eab78e9ba4
("refactor(measured_boot): remove passing of BL2 hash via device
tree") but was missed at the time.

Change-Id: Iced7e60af7ca660c342c0fc3a33b51865d67f04d
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

Makefile

@@ -449,10 +449,6 @@ DTC_FLAGS		+=	-I dts -O dtb
 DTC_CPPFLAGS		+=	-P -nostdinc -Iinclude -Ifdts -undef \
 				-x assembler-with-cpp $(DEFINES)
 
-ifeq ($(MEASURED_BOOT),1)
-DTC_CPPFLAGS		+=	-DMEASURED_BOOT -DBL2_HASH_SIZE=${TCG_DIGEST_SIZE}
-endif
-
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 # Common sources and include directories
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