Fix crc32 compile error

This fixes a compile error introduced with:

| commit 37f47a2a8c2dba420a849625b2926dacdc23cf49
| Author: Robert P. J. Day <rpjday@crashcourse.ca>
| Date:   Mon Jul 7 05:36:33 2014 -0400
|
|     crc32: Proper name of command is "crc32".
|
|     Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>