checkpatch: remove missing switch/case break test

This test doesn't work well and newer compilers are much better
at emitting this warning.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Cambda Zhu <cambda@linux.alibaba.com>
Link: http://lkml.kernel.org/r/7e25090c79f6a69d502ab8219863300790192fe2.camel@perches.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>