gcc-10: disable 'stringop-overflow' warning for now

This is the final array bounds warning removal for gcc-10 for now.

Again, the warning is good, and we should re-enable all these warnings
when we have converted all the legacy array declaration cases to
flexible arrays. But in the meantime, it's just noise.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Makefile

@@ -880,6 +880,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
 # We'll want to enable this eventually, but it's not going away for 5.7 at least
 KBUILD_CFLAGS += $(call cc-disable-warning, zero-length-bounds)
 KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds)
+KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow)
 
 # Enabled with W=2, disabled by default as noisy
 KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)