esp32/boards: Reduce size of D2WD and OTA firmware.

Commit c4e63ace66 enabled the SPI Ethernet
driver and that cost about 13k of firwmare size, pushing the firmware over
the limit of the D2WD and OTA board variants available size.

To fix, disable SPI Ethernet on the D2WD variant, and build the OTA variant
with size optimisation rather than performance optimisation.

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

ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd

@@ -3,6 +3,9 @@ CONFIG_COMPILER_OPTIMIZATION_SIZE=y
 CONFIG_COMPILER_OPTIMIZATION_PERF=n
 CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y
 
+# Disable SPI Ethernet driver to reduce firmware size.
+CONFIG_ETH_USE_SPI_ETHERNET=n
+
 CONFIG_ESPTOOLPY_FLASHMODE_DIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_40M=y
 CONFIG_ESPTOOLPY_FLASHSIZE_2MB=y

ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota

@@ -2,4 +2,6 @@ CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-4MiB-ota.csv"
 
 # Reduce firmware size to fit in the OTA partition.
+CONFIG_COMPILER_OPTIMIZATION_SIZE=y
+CONFIG_COMPILER_OPTIMIZATION_PERF=n
 CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y