core/download: properly honor BR_NO_CHECK_HASH_FOR when there's a hash

Before, if there was a hash for the affected file, it was checked
even if the package was in BR_NO_CHECK_HASH_FOR. This caused build
failures on gstreamer1 packages when BR2_PACKAGE_GSTREAMER1_GIT=y,
because the tarball was downloaded from an alternative source (git
tarball), the hash was different from the one in the official release,
and the hash check against the official hash failed.

Author: eocanha

support/download/check-hash

@@ -41,6 +41,13 @@ if [ ! -f "${h_file}" ]; then
     exit 0
 fi
 
+case " ${BR_NO_CHECK_HASH_FOR} " in
+*" ${base} "*)
+    # File explicitly has no hash
+    exit 0
+    ;;
+esac
+
 # Check one hash for a file
 # $1: known hash
 # $2: file (full path)