config-mpi: (Re-)enable MICROCODE_LATE_LOADING

Commit a77a94f (x86/microcode: Default-disable late loading)
introduced the Kconfig option, defaulting to no, so it was disabled in
our systems as it was backported to Linux v5.15.99 (commit
6d2b3a3).

We want to have the option, so reenable it.

config-mpi

@@ -44,6 +44,7 @@ CONFIG_GART_IOMMU=y
 CONFIG_NR_CPUS=512
 CONFIG_X86_MCELOG_LEGACY=y
 CONFIG_MICROCODE_AMD=y
+CONFIG_MICROCODE_LATE_LOADING=y
 CONFIG_X86_MSR=m
 CONFIG_X86_CPUID=m
 CONFIG_NUMA=y