clk: stm32mp1: add support of I2C6_K

Add support of missing I2C6_K with bit 3 of RCC_MC_APB5ENSETR =
I2C6EN: I2C6 peripheral clocks enable.

This patch allows customer to use I2C6 in SPL or in U-Boot
as other I2C instance, already support in clk driver.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
1 file changed