mmc-utils: expand .gitignore

Instead of adding .o and .o.d files for the files that are not
explicitly mentioned, add a pattern matching also all future files of
these types. This makes git status stop to mention

	3rdparty/hmac_sha/.hmac_sha2.o.d
	3rdparty/hmac_sha/.sha2.o.d
	3rdparty/hmac_sha/hmac_sha2.o
	3rdparty/hmac_sha/sha2.o
	.lsmmc.o.d
	lsmmc.o
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Chris Ball <chris@printf.net>

.gitignore

-.mmc.o.d
-.mmc_cmds.o.d
-mmc
-mmc.o
-mmc_cmds.o
+.*.o.d
+*.o
+/mmc