Change in coreboot[master]: soc/rockchip/rk3399/sdram: Introduce pctl_start

[Paul Menzel (Code Review)]

Attention is currently required from: Julius Werner, Moritz Fischer.
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51129 )

Change subject: soc/rockchip/rk3399/sdram: Introduce pctl_start
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Patch Set 1: Code-Review+1

(2 comments)

File src/soc/rockchip/rk3399/sdram.c:

https://review.coreboot.org/c/coreboot/+/51129/comment/a6f7004e_36b2d4d2 
PS1, Line 355: 			       channel);
It’d be great if you added, that it failed after 100 ms.

https://review.coreboot.org/c/coreboot/+/51129/comment/0235cb4f_b8146240 
PS1, Line 358: 	}
When stopping the time, I find it always nice to also add a debug or spew message, printing the time after the operation was completed.