checkpatch: fix false positive MISSING_BREAK warnings with --file

checkpatch: fix false positive MISSING_BREAK warnings with --file

Using --file mode can give false positives with MISSING_BREAK
fall-through warnings on simple but long multiple consecutive case
statements.

Look for all lines before a case statement for a switch or a statement
when using --file mode.

Fix a misspelling of preceded while there.

Signed-off-by: Joe Perches <[email protected]>
Reported-by: Lee Jones <[email protected]>
Acked-by: Lee Jones <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>