adb: Remove the obsolete include path to ext4_utils.

Since commit 778f500cd1d2c0d7efbec177eb52848f421091e4 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