mpc83xx: Fix dual I2C support for the MPC8349ITX, MPC8349EMDS, TQM834x, and MPC8360EMDS

This patch also adds an improved I2C set_speed(), which handles all clock
frequencies.

Signed-off-by: Timur Tabi <timur@freescale.com>
diff --git a/board/mpc8349emds/pci.c b/board/mpc8349emds/pci.c
index a916245..93827f1 100644
--- a/board/mpc8349emds/pci.c
+++ b/board/mpc8349emds/pci.c
@@ -75,10 +75,8 @@
 	/* Switch temporarily to I2C bus #2 */
 	orig_i2c_bus = i2c_get_bus_num();
 
-	if(orig_i2c_bus != I2C_BUS_2)
-	 	i2c_set_bus_num(I2C_BUS_2);
-
-	i2c_init(CFG_I2C_SPEED, CFG_I2C_SLAVE);
+	if(orig_i2c_bus != 2)
+	 	i2c_set_bus_num(2);
 
 	val8 = 0;
 	i2c_write(0x23, 0x6, 1, &val8, 1);
@@ -124,7 +122,7 @@
 	printf("PCI2: 32-bit on PMC3\n");
 #endif
 	/* Reset to original I2C bus */
-	if(orig_i2c_bus != I2C_BUS_2)
+	if(orig_i2c_bus != 2)
 	 	i2c_set_bus_num(orig_i2c_bus);
 }