Change in coreboot[master]: soc/intel/fast_spi: Use `need_restore_mtrr()` to clear temp MTRR

[Lean Sheng Tan (Code Review)]

Attention is currently required from: Subrata Banik, Werner Zeh.
Lean Sheng Tan has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/63492 )

Change subject: soc/intel/fast_spi: Use `need_restore_mtrr()` to clear temp MTRR
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Patch Set 2: -Code-Review

(1 comment)

Patchset:

PS2: 
I think this CL is not needed as Arthur's CL has been merged. Thanks everyone