target: consolidate existing target/algo common_magic

Unify common_magic type to unsigned int
Move common_magic to be the first member of the struct
Add unsigned specifier to xxx_COMMON_MAGIC #defines

Change-Id: If961d33232698529514ba3720e04418baf6dc6fe
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/6996
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/target/mips_m4k.h

@@ -15,10 +15,11 @@
 
 struct target;
 
-#define MIPSM4K_COMMON_MAGIC	0xB321B321
+#define MIPSM4K_COMMON_MAGIC	0xB321B321U
 
 struct mips_m4k_common {
-	uint32_t common_magic;
+	unsigned int common_magic;
+
 	bool is_pic32mx;
 	struct mips32_common mips32;
 };