build: fix typo in cmake patch

The variable in the case argument was mistyped, so the case always
checked against an empty string and never matched.

Fix the variable name.

Signed-off-by: Piotr Stefaniak <pstef@freebsd.org>
[add commit message]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

tools/cmake/patches/130-bootstrap_parallel_make_flag.patch

@@ -5,7 +5,7 @@
  cmake_original_make_flags="${cmake_make_flags}"
  if [ "x${cmake_parallel_make}" != "x" ]; then
 -  cmake_make_flags="${cmake_make_flags} -j ${cmake_parallel_make}"
-+  case "$cmake_paralle_make" in
++  case "$cmake_parallel_make" in
 +    [0-9]*) cmake_parallel_make="-j ${cmake_parallel_make}";;
 +  esac
 +  cmake_make_flags="${cmake_make_flags} ${cmake_parallel_make}"