ARM: mach-shmobile: do not enable the PLLC2 clock on init

AP4EVB has to reparent PLLC2 to provide a precise HDMI clock, this is only
possible, if PLLC2 hasn't been enabled yet. Since no other driver currently
uses PLLC2 we can safely remove the CLK_ENABLE_ON_INIT flag. This fixes
the "Cannot set PLLC2 parent: -16, 1 users" error message, when trying to
use HDMI on AP4EVB.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>