core: adjust nsec ddr memory size correctly

In carve_out_phys_mem(), when pa has the same address
with m[n].addr, the m[n].size should also be adjusted.

Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Fangsuo Wu <fangsuowu@asrmicro.com>
diff --git a/core/arch/arm/mm/core_mmu.c b/core/arch/arm/mm/core_mmu.c
index 93a2c07..866d53b 100644
--- a/core/arch/arm/mm/core_mmu.c
+++ b/core/arch/arm/mm/core_mmu.c
@@ -301,6 +301,7 @@
 		*mem = m;
 	} else if (pa == m[n].addr) {
 		m[n].addr += size;
+		m[n].size -= size;
 	} else if ((pa + size) == (m[n].addr + m[n].size)) {
 		m[n].size -= size;
 	} else {