Change in coreboot[master]: mb/google/dedede/var/storo: Support LTE module

[zanxi chen (Code Review)]

Attention is currently required from: Martin Roth, Henry Sun, Paul Menzel, Tao Xia, Weimin Wu, Karthik Ramasubramanian.
zanxi chen has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51017 )

Change subject: mb/google/dedede/var/storo: Support LTE module
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Patch Set 5:

(5 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/51017/comment/83497173_5dcb1d5b 
PS2, Line 14: TEST=LTE function is OK
> Flash firmware and insert the SIM card to connect to the network.

Done

https://review.coreboot.org/c/coreboot/+/51017/comment/b99c1c57_34a5f722 
PS2, Line 14: TEST=LTE function is OK
> Flash firmware and insert the SIM card to connect to the network.

Done

File src/mainboard/google/dedede/variants/storo/Makefile.inc:

https://review.coreboot.org/c/coreboot/+/51017/comment/a964ee14_f645c620 
PS2, Line 5: smm-y += variant.c
> Powering off LTE module will follow the system shutdown.

Done

File src/mainboard/google/dedede/variants/storo/variant.c:

https://review.coreboot.org/c/coreboot/+/51017/comment/872a59df_dbc5280c 
PS2, Line 11: 	mdelay(20);
> It's refer to spec about LTE850.

Done

https://review.coreboot.org/c/coreboot/+/51017/comment/e9b66539_8cacc530 
PS2, Line 11: 	mdelay(20);
> It's refer to spec about LTE850.

Done