Add option to set spi controller clock frequency via device tree
using standard clock bindings.
Define dw_spi_get_clk function as 'weak' as some targets
(like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) don't use standard clock API
and implement dw_spi_get_clk their own way in their clock manager.
Get rid of clock_manager.h include as we don't use
cm_get_spi_controller_clk_hz function anymore. (we use redefined
dw_spi_get_clk in SOCFPGA clock managers instead)
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
58c125b9e2