[Mellanox] Remove unnecessary file manipulation in the SAI Make file (#15993) (#16101)

Signed-off-by: Kebo Liu <[email protected]>
Co-authored-by: Kebo Liu <[email protected]>

Author: mssonicbld

platform/mellanox/mlnx-sai/Makefile

@@ -9,7 +9,6 @@ $(addprefix $(DEST)/, $(MAIN_TARGET)): $(DEST)/% :
 	pushd SAI-Implementation
 	pushd mlnx_sai
 
-	chmod a+x autogen.sh
 	debuild -e 'make_extra_flags="DEFS=-DACS_OS -DCONFIG_SYSLOG"' -us -uc -d -b
 	popd