bdk: use size defines where applicable

bdk/utils/util.h

@@ -73,7 +73,7 @@ typedef struct _nyx_storage_t
 	u32 cfg;
 	u8  irama[0x8000];
 	u8  hekate[0x30000];
-	u8  rsvd[0x800000 - sizeof(nyx_info_t)];
+	u8  rsvd[SZ_8M - sizeof(nyx_info_t)];
 	nyx_info_t info;
 	mtc_config_t mtc_cfg;
 	emc_table_t mtc_table[10];