Provide strcmp_P where needed (#18103)

Marlin/src/HAL/LINUX/HAL.h

 FORCE_INLINE static void DELAY_CYCLES(uint64_t x) {
   Clock::delayCycles(x);
 }
+
+// Add strcmp_P if missing
+#ifndef strcmp_P
+  #define strcmp_P(a, b) strcmp((a), (b))
+#endif

Marlin/src/HAL/LPC1768/HAL.h

 // Reset source
 void HAL_clear_reset_source(void);
 uint8_t HAL_get_reset_source(void);
+
+// Add strcmp_P if missing
+#ifndef strcmp_P
+  #define strcmp_P(a, b) strcmp((a), (b))
+#endif