x86/microcode/AMD: Fix patch level reporting for family 15h

On AMD family 14h, applying microcode patch on the a core (core0)
would also affect the other core (core1) in the same compute
unit. The driver would skip applying the patch on core1, but it
still need to update kernel structures to reflect the proper
patch level.

The current logic is not updating the struct
ucode_cpu_info.cpu_sig.rev of the skipped core. This causes the
/sys/devices/system/cpu/cpu1/microcode/version to report
incorrect patch level as shown below:

$ grep . cpu?/microcode/version
cpu0/microcode/version:0x600063d
cpu1/microcode/version:0x6000626
cpu2/microcode/version:0x600063d
cpu3/microcode/version:0x6000626
cpu4/microcode/version:0x600063d

Signed-off-by: Suravee Suthikulpanit <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Cc: <[e-mail]>
Cc: <[e-mail]>
Cc: <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/kernel/microcode_amd.c

···
 	/* need to apply patch? */
 	if (rev >= mc_amd->hdr.patch_id) {
 		c->microcode = rev;
+		uci->cpu_sig.rev = rev;
 		return 0;
 	}