Fix, consolidate PSTR aliases (#20812)

Co-authored-by: Jason Smith <jason.inet@gmail.com>
Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/HAL/STM32F1/HAL.h

@@ -152,14 +152,6 @@ void HAL_idletask();
 // On AVR this is in math.h?
 #define square(x) ((x)*(x))
 
-#ifndef strncpy_P
-  #define strncpy_P(dest, src, num) strncpy((dest), (src), (num))
-#endif
-
-// Fix bug in pgm_read_ptr
-#undef pgm_read_ptr
-#define pgm_read_ptr(addr) (*(addr))
-
 #define RST_POWER_ON   1
 #define RST_EXTERNAL   2
 #define RST_BROWN_OUT  4