Patch merged into coreboot/master: amd/amdht: Fix format security errors

the following patch was just integrated into master:
commit f6776fa62c84ae516f84c99859d826f77d508079
Author: Paul Menzel 
Date:   Fri Jan 20 14:49:35 2017 +0100

amd/amdht: Fix format security errors

Ubuntu’s default compiler flags for GCC [1][2] include `-Wformat
    -Wformat-security`, causing errors similar like the one below.

```
        CC         romstage/northbridge/amd/amdht/ht_wrapper.o
    src/northbridge/amd/amdht/ht_wrapper.c: In function 'AMD_CB_EventNotify':
    src/northbridge/amd/amdht/ht_wrapper.c:124:4: error: format not a string literal and no format arguments [-Werror=format-security]
        printk(log_level, event_class_string_decodes[evtClass]);
        ^
    […]
    ```

Fix that, by explicitly using a format string.

TEST=Built and booted on ASUS KGPE-D16.

[1] https://stackoverflow.com/questions/17260409/fprintf-error-format-not-a-stri...
        "fprintf, error: format not a string literal and no format arguments [-Werror=format-security"
    [2] I tested with gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609.

Change-Id: Iabe60deeffa441146eab31dac4416846ce95c32a
    Signed-off-by: Paul Menzel 
    Reviewed-on: https://review.coreboot.org/18208
    Tested-by: build bot (Jenkins)
    Reviewed-by: Nico Huber

See https://review.coreboot.org/18208 for details.

-gerrit