[coreboot-gerrit] Change in coreboot[master]: [TEST] Add support for link time optimization

[Paul Menzel (Code Review)]

Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/38989 )

Change subject: [TEST] Add support for link time optimization
......................................................................

Patch Set 6:

Keith, as you also seem to care about image size, could you please test, if this still works on your Intel 440BX boards?

Size reduction for the asus/p2b (P2B-LS) seems also ten to 13 percent:

1.  Without LTO:

```
    fallback/romstage              0x80       stage           16412 none
    cpu_microcode_blob.bin         0x4100     microcode       83968 none
    fallback/ramstage              0x18980    stage           50347 none
    ```

2.  With LTO:

```
    fallback/romstage              0x80       stage           14212 none
    cpu_microcode_blob.bin         0x3880     microcode       83968 none
    fallback/ramstage              0x18100    stage           44882 none
    ```