74xx_7xx: Fix rounding problem in CPU frequency calculation

This patch fixes a problem in the CPU frequency calculation. Without it
a 798MHz CPU is displayed as 368.503 MHz. And with it it's 798 MHz.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/cpu/74xx_7xx/speed.c b/cpu/74xx_7xx/speed.c
index bc33a67..f2fdcd5 100644
--- a/cpu/74xx_7xx/speed.c
+++ b/cpu/74xx_7xx/speed.c
@@ -149,8 +149,8 @@
 
 	case CPU_750GX:
 	case CPU_750FX:
-		clock = gd->bus_clk *
-			hid1_fx_multipliers_x_10[get_hid1 () >> 27] / 10;
+		clock = (gd->bus_clk / 10) *
+			hid1_fx_multipliers_x_10[get_hid1 () >> 27];
 		break;
 
 	case CPU_7450: