ENGR00243315-3 MXC V4L2 Capture:Remove unnecessary mclk setting

ENGR00243315-3 MXC V4L2 Capture:Remove unnecessary mclk setting

commit f8e1a3bb62eecf93a31a51c4dbe08a0214fa1d57 added a hard
coding for csi_parma.mclk setting to 27MHz. The comment added by
that commit is totally wrong by telling that csi_param.mclk
would be a kind of 'pixel clock' set in 'csi_data_dest' register.
This patch removes the unnecessary mclk setting for csi_param.mclk
variable, since it is only valid for CSI test mode.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit 5fed1e3fde2d63c80f414f204734d35ceecef561)