spl: Convert spl_ymodem_load_image() to use linker list

Add a linker list declaration for this method and remove the explicit
switch() code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/spl/spl.c

@@ -384,10 +384,6 @@ static int spl_load_image(u32 boot_device)
 		return loader->load_image(&bootdev);
 
 	switch (boot_device) {
-#ifdef CONFIG_SPL_YMODEM_SUPPORT
-	case BOOT_DEVICE_UART:
-		return spl_ymodem_load_image(&bootdev);
-#endif
 #if defined(CONFIG_SPL_SPI_SUPPORT) || defined(CONFIG_SPL_SPI_FLASH_SUPPORT)
 	case BOOT_DEVICE_SPI:
 		return spl_spi_load_image(&bootdev);

common/spl/spl_ymodem.c

@@ -68,7 +68,7 @@ static ulong ymodem_read_fit(struct spl_load_info *load, ulong offset,
 	return size;
 }
 
-int spl_ymodem_load_image(struct spl_boot_device *bootdev)
+static int spl_ymodem_load_image(struct spl_boot_device *bootdev)
 {
 	int size = 0;
 	int err;
@@ -132,3 +132,4 @@ end_stream:
 	printf("Loaded %d bytes\n", size);
 	return 0;
 }
+SPL_LOAD_IMAGE_METHOD(0, BOOT_DEVICE_UART, spl_ymodem_load_image);

include/spl.h

@@ -181,9 +181,6 @@ struct spl_image_loader {
 		.load_image = __method, \
 	}
 
-/* YMODEM SPL functions */
-int spl_ymodem_load_image(struct spl_boot_device *bootdev);
-
 /* SPI SPL functions */
 int spl_spi_load_image(struct spl_boot_device *bootdev);