MPC837x: set i2c1_clk

 Running on mpc837x without CONFIG_FSL_ESDHC leads to
 i2c1_clk not being set at all. It is bound to clock
 of encryption module. fix this.

Signed-off-by: Andre Schwarz <andre.schwarz@matrix-vision.de>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>