Change file permission of checkvintf binary

Make checkvintf binary executable by setting file permission to
755

Test: development/vndk/tools/build_mixed -v 8.1.0
-m development/vndk/tools/modify_system_img.sh
system_dir device_dir out_dir system_dir/checkvintf
Bug: 74214049

Merged-In: Ic87a736b5a9e7c64fd69fac76404994fabff635f
Change-Id: Ic87a736b5a9e7c64fd69fac76404994fabff635f
(cherry picked from commit f82df5a7)