mimxrt: Improve PSRAM implementation.

Enable PSRAM by default for Teensy 4.1,
update license info, uncrustify psram.c
and main.c, and remove FLASHMEM macro.

Signed-off-by: Dryw Wade <dryw.wade@sparkfun.com>

Author: sfe-SparkFro

ports/mimxrt/boards/TEENSY41/mpconfigboard.h

@@ -136,3 +136,6 @@
     { IOMUXC_GPIO_B1_11_ENET_RX_ER, 0, 0xB0E9u }, \
     { IOMUXC_GPIO_B1_15_ENET_MDIO, 0, 0xB0E9u }, \
     { IOMUXC_GPIO_B1_14_ENET_MDC, 0, 0xB0E9u },
+
+// Enable PSRAM support
+#define MICROPY_HW_ENABLE_PSRAM (1)

ports/mimxrt/main.c

@@ -107,7 +107,7 @@ int main(void) {
         mp_cstack_init_with_top(&_estack, &_estack - &_sstack);
 
         #if MICROPY_HW_ENABLE_PSRAM
-        if(psram_size) {
+        if (psram_size) {
             #if MICROPY_GC_SPLIT_HEAP
             gc_init(&_gc_heap_start, &_gc_heap_end);
             gc_add((void *)PSRAM_BASE, (void *)(PSRAM_BASE + psram_size));