UPSTREAM: 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.

BUG=None
TEST=Compile

Signed-off-by: Uwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Chris Ball <chris@printf.net>
(cherry picked from commit a1a6120c34133d87bedfb04ab06ce43097c5e0d2)
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>

Change-Id: Iff5169b84d7981bff0e9ea2ba7ccc8476b6b69cf
Reviewed-on: https://chromium-review.googlesource.com/1114454
Commit-Ready: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
diff --git a/mmc_cmds.c b/mmc_cmds.c
index b158106..ee5a802 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -49,6 +49,10 @@
 
 #include "3rdparty/hmac_sha/hmac_sha2.h"
 
+#ifndef offsetof
+#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+#endif
+
 #define WP_BLKS_PER_QUERY 32
 
 #define USER_WP_PERM_PSWD_DIS	0x80