x86/CPU/AMD: Terminate the erratum_1386_microcode array

The erratum_1386_microcode array requires an empty entry at the end.
Otherwise x86_match_cpu_with_stepping() will continue iterate the array after
it ended.

Add an empty entry to erratum_1386_microcode to its end.

Fixes: 29ba89f1 ("x86/CPU/AMD: Improve the erratum 1386 workaround")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20241126134722.480975-1-bigeasy@linutronix.de