linux-4.14.18: Select CONFIG_X86_MCELOG_LEGACY

Select `CONFIG_X86_MCELOG_LEGACY` so the device `/dev/mcelog` needed by
[mcelog][1] is created.

Commit 5de97c9f (x86/mce: Factor out and deprecate the /dev/mcelog
driver) introduces this option, and is present since Linux 4.12.

[1]: https://www.mcelog.org/

Fixes: #605

linux-4.14.18-206.bee

@@ -155,6 +155,7 @@ mee_configure() {
 	CONFIG_GART_IOMMU=y
 	CONFIG_NR_CPUS=256
 	CONFIG_PREEMPT_VOLUNTARY=y
+	CONFIG_X86_MCELOG_LEGACY=y
 	CONFIG_MICROCODE_AMD=y
 	CONFIG_NUMA=y
 	CONFIG_TRANSPARENT_HUGEPAGE=y