esp8266: Add FLASH_MODE,FLASH_SIZE options for make deploy target.

Added options to make deploy so it can be used for ESP8266 boards with
other flash configurations.  For example NodeMCU DEVKIT V1.0 can now use:

    $ make FLASH_MODE=dio FLASH_SIZE=32m deploy

esp8266/Makefile

@@ -18,6 +18,8 @@ FROZEN_DIR = scripts
 FROZEN_MPY_DIR = modules
 PORT ?= /dev/ttyACM0
 BAUD ?= 115200
+FLASH_MODE ?= qio
+FLASH_SIZE ?= 8m
 CROSS_COMPILE = xtensa-lx106-elf-
 ESP_SDK = $(shell $(CC) -print-sysroot)/usr
 
@@ -189,7 +191,7 @@ $(BUILD)/frozen_mpy.c: $(FROZEN_MPY_MPY_FILES) $(BUILD)/genhdr/qstrdefs.generate
 
 deploy: $(BUILD)/firmware-combined.bin
 	$(ECHO) "Writing $< to the board"
-	$(Q)esptool.py --port $(PORT) --baud $(BAUD) write_flash --verify --flash_size=8m 0 $<
+	$(Q)esptool.py --port $(PORT) --baud $(BAUD) write_flash --verify --flash_size=$(FLASH_SIZE) --flash_mode=$(FLASH_MODE) 0 $<
 	#$(Q)esptool.py --port $(PORT) --baud $(BAUD) write_flash --flash_size=8m 0 $(BUILD)/firmware.elf-0x00000.bin 0x9000 $(BUILD)/firmware.elf-0x0[1-f]000.bin
 
 reset:

esp8266/README.md

@@ -70,9 +70,10 @@ $ make deploy
 ```
 This will use the `esptool.py` script to download the images.  You must have
 your ESP module in the bootloader mode, and connected to a serial port on your PC.
-The default serial port is `/dev/ttyACM0`.  To specify another, use, eg:
+The default serial port is `/dev/ttyACM0`, flash mode is `qio` and flash size is `8m`.
+To specify other values, use, eg:
 ```bash
-$ make PORT=/dev/ttyUSB0 deploy
+$ make PORT=/dev/ttyUSB0 FLASH_MODE=qio FLASH_SIZE=8m deploy
 ```
 
 The image produced is `firmware-combined.bin`, to be flashed at 0x00000.