clk: qcom: gcc: Fix board clock node name

Device tree node name are not supposed to have "_" in them so fix the
node name use of xo_board to xo-board

Fixes: 652f1813

 ("clk: qcom: gcc: Add global clock controller driver for QCS404")
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>