configs: Rename CONFIG_IMAGE_FORMAT_LEGACY to CONFIG_LEGACY_IMAGE_FORMAT

The name CONFIG_LEGACY_IMAGE_FORMAT reads slightly better along with
allowing us to avoid a rather nasty Kbuild/Kconfig issue down the line
with CONFIG_IS_ENABLED(IMAGE_FORMAT_LEGACY).  In a few places outside of
cmd/ switch to using CONFIG_IS_ENABLED() to test what is set.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/common/image.c b/common/image.c
index 75b84d5..9f9538f 100644
--- a/common/image.c
+++ b/common/image.c
@@ -38,7 +38,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#if defined(CONFIG_IMAGE_FORMAT_LEGACY)
+#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
 static const image_header_t *image_get_ramdisk(ulong rd_addr, uint8_t arch,
 						int verify);
 #endif
@@ -377,7 +377,7 @@
 
 
 #ifndef USE_HOSTCC
-#if defined(CONFIG_IMAGE_FORMAT_LEGACY)
+#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
 /**
  * image_get_ramdisk - get and verify ramdisk image
  * @rd_addr: ramdisk image start address
@@ -867,7 +867,7 @@
  */
 int genimg_get_format(const void *img_addr)
 {
-#if defined(CONFIG_IMAGE_FORMAT_LEGACY)
+#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
 	const image_header_t *hdr;
 
 	hdr = (const image_header_t *)img_addr;
@@ -933,7 +933,7 @@
 {
 	ulong rd_addr, rd_load;
 	ulong rd_data, rd_len;
-#if defined(CONFIG_IMAGE_FORMAT_LEGACY)
+#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
 	const image_header_t *rd_hdr;
 #endif
 	void *buf;
@@ -1025,7 +1025,7 @@
 		 */
 		buf = map_sysmem(rd_addr, 0);
 		switch (genimg_get_format(buf)) {
-#if defined(CONFIG_IMAGE_FORMAT_LEGACY)
+#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
 		case IMAGE_FORMAT_LEGACY:
 			printf("## Loading init Ramdisk from Legacy "
 					"Image at %08lx ...\n", rd_addr);