ports/rp2: Move PSRAM init earlier in startup.

Try to avoid causing an upset with USB startup by
detecting PSRAM as early as possible.

Signed-off-by: Phil Howard <github@gadgetoid.com>

Author: Gadgetoid

ports/rp2/main.c

@@ -86,6 +86,10 @@ int main(int argc, char **argv) {
     SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
     #endif
 
+    #if defined(MICROPY_HW_PSRAM_CS_PIN) && MICROPY_HW_ENABLE_PSRAM
+    size_t psram_size = psram_init(MICROPY_HW_PSRAM_CS_PIN);
+    #endif
+
     pendsv_init();
     soft_timer_init();
 
@@ -127,7 +131,6 @@ int main(int argc, char **argv) {
     mp_cstack_init_with_top(&__StackTop, &__StackTop - &__StackBottom);
 
     #if defined(MICROPY_HW_PSRAM_CS_PIN) && MICROPY_HW_ENABLE_PSRAM
-    size_t psram_size = psram_init(MICROPY_HW_PSRAM_CS_PIN);
     if (psram_size) {
         #if MICROPY_GC_SPLIT_HEAP
         gc_init(&__GcHeapStart, &__GcHeapEnd);