powerpc: mpc512x: Add support for get_svr() for mpc512x devices

Defines get_svr() for mpc512x devices

Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: York Sun <york.sun@nxp.com>

arch/powerpc/cpu/mpc512x/start.S

@@ -443,6 +443,11 @@ get_pvr:
 	mfspr	r3, PVR
 	blr
 
+	.globl get_svr
+get_svr:
+	mfspr	r3, SVR
+	blr
+
 /*-------------------------------------------------------------------*/
 
 /*