mmc-utils: move offsetof from mmc.h to only user

offsetof isn't mmc specific, so remove it from mmc.h. As there is only a
single user define it there.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Chris Ball <chris@printf.net>
2 files changed