ci: fix arm64 config filename

The ARM64 config file has been renamed in the commit
ae2f2fe ("build: rename linuxapp to linux in meson cross files").

Fixes: 99889bd ("ci: introduce Travis builds for GitHub repositories")

Signed-off-by: David Marchand <[email protected]>
Acked-by: Aaron Conole <[email protected]>

Author: david-marchand

.ci/linux-build.sh

@@ -16,7 +16,7 @@ trap on_error EXIT
 
 if [ "$AARCH64" = "1" ]; then
     # convert the arch specifier
-    OPTS="$OPTS --cross-file config/arm/arm64_armv8_linuxapp_gcc"
+    OPTS="$OPTS --cross-file config/arm/arm64_armv8_linux_gcc"
 fi
 
 OPTS="$OPTS --default-library=$DEF_LIB"