flash-size agnostic builds (#6690)

* flash: mapping definition by sketch at runtime depending on flash chip size and user configuration

tests/host/common/flash_hal_mock.cpp

@@ -3,6 +3,8 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "flash_hal.h"
+
 extern "C"
 {
     uint32_t s_phys_addr = 0;