esp32/boards: Enable further IRAM saving opts to fit ESP32-SPIRAM fw.

The amount of free IRAM in ESP32 SPIRAM builds is very small and went over
the limit due to commit 30b0ee34d3.  This
commit enables further optimisations to reduce IRAM usage.

Signed-off-by: Damien George <damien@micropython.org>

ports/esp32/boards/sdkconfig.spiram

@@ -12,4 +12,7 @@ CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192
 # SPIRAM increases the size of the firmware and overflows iram0_0_seg, due
 # to PSRAM bug workarounds.  Apply some options to reduce the firmware size.
 CONFIG_COMPILER_OPTIMIZATION_SIZE=y
+CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y
+CONFIG_RINGBUF_PLACE_FUNCTIONS_INTO_FLASH=y
 CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH=y
+CONFIG_FREERTOS_PLACE_SNAPSHOT_FUNS_INTO_FLASH=y