checkpatch.pl discourages the use of spaces at the beginning of lines.
Some of the CTL_ELEM defines were not properly indented.

This patch replaces the leading spaces by tabs. No functionality is
changed, the commit is purely cosmetic.
Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>