[Patch] Correct error in setting spi clock for ecspi3 in imx8mp u-boot

[PhilRittenhouse]

I ran into the following issue with the u-boot code from the IMX8MPLUS EVK, and thought others might benefit from what I found

When adding u-boot SPI support for the FRAM in our design, I opted to just enable the ECSPI3 bus so that we could test the FRAM using the SSPI command. Unfortunately, I found that the SPI bus clock was not getting set correctly.

After doing a lot of digging, I discovered that the spi_cfg_mxc() function was always calling mxc_get_clock() for ecspi1 instead of ecspi3. This meant it was using the wrong clock when configuring ecspi3. Attached are the changes I made to the U-Boot code to fix the bug

[Zhiming_Liu]

Hello @PhilRittenhouse 

Suggest you can change this title like:

[Patch] Correct the error setting about ecspi3 boot on i.MX8MP

[PhilRittenhouse]

Done. Thanks