m68knommu: fix clock rate value reported for ColdFire 54xx parts

The instruction timings of the ColdFire 54xx family parts are
different to other version 4 parts (or version 2 or 3 parts for
that matter too).

Move the instruction timing setting into the ColdFire part
specific headers, and set the 54xx value appropriately.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
diff --git a/arch/m68k/include/asm/m520xsim.h b/arch/m68k/include/asm/m520xsim.h
index afa2118..85b39ed 100644
--- a/arch/m68k/include/asm/m520xsim.h
+++ b/arch/m68k/include/asm/m520xsim.h
@@ -11,7 +11,8 @@
 #define m520xsim_h
 /****************************************************************************/
 
-#define	CPU_NAME	"COLDFIRE(m520x)"
+#define	CPU_NAME		"COLDFIRE(m520x)"
+#define	CPU_INSTR_PER_JIFFY	3
 
 /*
  *  Define the 520x SIM register set addresses.