uboot-imx

stm32mp1: clk: define RCC_PLLNCFGR2_SHIFT macro

This patch define RCC_PLLNCFGR2_SHIFT to reuse it in
the pll function for set rate.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Vikas Manocha <vikas.manocha@st.com>