Target specific nxplpc and ststm32 pio platform versions to fix build (#11506)

platformio.ini

 # NXP LPC1768 ARM Cortex-M3
 #
 [env:LPC1768]
-platform          = nxplpc
+platform          = nxplpc@<3.4.0
 board             = lpc1768
 board_build.f_cpu = 100000000L
 # Override default maximum RAM. LPC1768/9 do have 64k, but in 3 blocks (32K, 16K, 16K).
 # STM32F103RE
 #
 [env:STM32F1]
-platform      = ststm32
+platform      = ststm32@<4.4.0
 framework     = arduino
 board         = genericSTM32F103RE
 build_flags   = !python Marlin/src/HAL/HAL_STM32F1/stm32f1_flag_script.py