product/sgi575: fix gtimer module config in mcp ramfw

Set the control register in the gtimer config data to GENERIC REFCLK
CNTControl address. Set skip_cntcontrol_init flag to true since MCP
cannot configure the CNTCONTROL register which is accessible by secure
accesses only.

The configuration of this register will be done by the gtimer module in
scp ramfw.

Signed-off-by: Shriram K <shriram.k@arm.com>
Change-Id: If80e71b0b99306dd28924ad2398e831b294786ea