r600/sfn: Initialize GPRValue member m_pin_to_channel.

Fix defects reported by Coverity Scan.

Uninitialized scalar field (UNINIT_CTOR) uninit_member: Non-static class member m_pin_to_channel is not initialized in this constructor nor in any functions that it calls.

Signed-off-by: Vinson Lee vlee@freedesktop.org

cc: @gerddie