libc: minimal: Use zephyr include instead of system include

Using zephyr_include_directories() instead of
zephyr_system_include_directories places include before toolchain
include for some setup.

Author: finikorg

lib/libc/minimal/CMakeLists.txt

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 
-zephyr_system_include_directories(include)
+zephyr_include_directories(include)
 
 zephyr_library()
 zephyr_library_sources(