x86/ucode: Drop the match_reg[] field from AMD's microcode_patch

This was true in the K10 days, but even back then the match registers were
really payload data rather than header data.

But, it's really model specific data, and these days typically part of the
signature, so is random data for all intents and purposes.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/cpu/microcode/amd.c

@@ -48,7 +48,6 @@ struct microcode_patch {
     uint8_t  sb_rev_id;
     uint8_t  bios_api_rev;
     uint8_t  reserved1[3];
-    uint32_t match_reg[8];
 };
 
 #define UCODE_MAGIC                0x00414d44