MLK-21052-09 soc: imx: Fix building without HAVE_IMX_SRC

If support for imx_src_is_m4_enabled is not compiled then just return
the default value "false".

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>

include/soc/imx/src.h

 #ifndef __SOC_IMX_SRC_H
 #define __SOC_IMX_SRC_H
 
+#if defined(CONFIG_HAVE_IMX_SRC)
 bool imx_src_is_m4_enabled(void);
+#else
+static inline bool imx_src_is_m4_enabled(void) { return false; }
+#endif
 
 #endif /* __SOC_IMX_SRC_H */