[U-Boot] [PATCH v4 12/13] clk: Port Linux common clock framework

This commit brings the files from Linux kernel to provide clocks support as it is used on the Linux kernel with common clock framework [CCF] setup. The directory structure has been preserved. The ported code only supports reading information from PLL, MUX, Divider, etc and enabling/disabling the clocks USDHCx/ECSPIx depending on used bus. Moreover, it is agnostic to the alias numbering as the information about the clock is read from device tree. One needs to pay attention to the comments indicating necessary for U-boot's DM changes. If needed the code can be extended to support the "set" part of the clock management. Signed-off-by: Lukasz Majewski lukma@denx.de

Applied to u-boot-imx, master, thanks !

Best regards, Stefano Babic