Fix(extra mem): Fix additonal memory allocation for MPU-based systems #339

Job	Run time
build-arm (fvp-a, GICV2)	1m 30s
build-arm (fvp-a, GICV2, CROSS_COMPILE=clang)	1m 29s
build-arm (fvp-a, GICV3)	1m 28s
build-arm (fvp-a, GICV3, CROSS_COMPILE=clang)	1m 30s
build-arm (fvp-a-aarch32, GICV2)	1m 28s
build-arm (fvp-a-aarch32, GICV2, CROSS_COMPILE=clang)	1m 29s
build-arm (fvp-a-aarch32, GICV3)	1m 29s
build-arm (fvp-a-aarch32, GICV3, CROSS_COMPILE=clang)	1m 30s
build-arm (fvp-r, GICV2)	1m 29s
build-arm (fvp-r, GICV2, CROSS_COMPILE=clang)	1m 28s
build-arm (fvp-r, GICV3)	1m 28s
build-arm (fvp-r, GICV3, CROSS_COMPILE=clang)	1m 29s
build-arm (fvp-r-aarch32, GICV2)	1m 28s
build-arm (fvp-r-aarch32, GICV2, CROSS_COMPILE=clang)	1m 28s
build-arm (fvp-r-aarch32, GICV3)	1m 29s
build-arm (fvp-r-aarch32, GICV3, CROSS_COMPILE=clang)	1m 27s
	23m 39s

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