hidl-gen: Match exact string in hidl-gen before skipping.

- Grep leads to a substring match and causes package
  names to get skipped incorrectly. Use -w option to
  find the exact match.

CRs-Fixed: 2479486
Change-Id: Ic1fbe72304177d396eab142eaf832b841b61da24

vendor_hal_makefile_generator.sh

@@ -91,7 +91,7 @@ function generate_make_files() {
         hal_package=${hal_package%?}
 
         #Check if we already executed hidl-gen for a given package
-        if ${ECHO} "${package_collection[@]}" | ${GREP} $hal_package > /dev/null; then
+        if ${ECHO} "${package_collection[@]}" | ${GREP} -w $hal_package > /dev/null; then
             continue;
         else
             package_collection+=($hal_package)