x86/purgatory: disable KMSAN instrumentation

The stand-alone purgatory.ro does not contain the KMSAN runtime, therefore
it can't be built with KMSAN compiler instrumentation.

Link: https://lkml.kernel.org/r/[email protected]
Link: google/kmsan#89
Signed-off-by: Alexander Potapenko <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: ramosian-glider

arch/x86/purgatory/Makefile

@@ -26,6 +26,7 @@ GCOV_PROFILE	:= n
 KASAN_SANITIZE	:= n
 UBSAN_SANITIZE	:= n
 KCSAN_SANITIZE	:= n
+KMSAN_SANITIZE	:= n
 KCOV_INSTRUMENT := n
 
 # These are adjustments to the compiler flags used for objects that