imx: mx6 remove duplicated enable_cspi_clock

enable_spi_clock does the same thing with enable_cspi_clock, so
remove enable_cspi_clock.
Remove enable_cspi_clock prototype in header file
convert cm_fx6/spl.c to use enable_spi_clk

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
3 files changed