adb: Remove the obsolete include path to ext4_utils.

Since commit 8ad80763e4b3bdcd80d16c63f03b19eb9df989b2 has removed
'#include "ext4_sb.h"', there's no more reference to ext4_utils headers.

Test: `mmma system/core/adb`

Change-Id: I7ca1a6e91f1e0de84238c2a7facbebe9600a3d87
1 file changed