x86/microcode/AMD: Increase microcode PATCH_MAX_SIZE

Future AMD CPUs will have microcode patches that exceed the default 4K
patch size. Raise our limit.
Signed-off-by: John Allen <john.allen@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org # v4.14..
Link: https://lkml.kernel.org/r/20200409152931.GA685273@mojo.amd.com

arch/x86/include/asm/microcode_amd.h

@@ -41,7 +41,7 @@ struct microcode_amd {
 	unsigned int			mpb[0];
 };
 
-#define PATCH_MAX_SIZE PAGE_SIZE
+#define PATCH_MAX_SIZE (3 * PAGE_SIZE)
 
 #ifdef CONFIG_MICROCODE_AMD
 extern void __init load_ucode_amd_bsp(unsigned int family);