scripts/mod/modpost.c: fix spelling of module and happens

Spelling fixes in scripts/mod/modpost.c

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>