spl: Rename Kconfig SPL_LEGACY_IMAGE_SUPPORT to SPL_LEGACY_IMAGE_FORMAT

This matches what this support is called in the non-SPL case. The postfix
_SUPPORT is redundant as enabling Kconfig options implies support.
With this we can use CONFIG_IS_ENABLED() as needed.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/openpiton_riscv64_spl_defconfig b/configs/openpiton_riscv64_spl_defconfig
index cbcbe42..8a7e3cc 100644
--- a/configs/openpiton_riscv64_spl_defconfig
+++ b/configs/openpiton_riscv64_spl_defconfig
@@ -20,7 +20,7 @@
 # CONFIG_ARCH_FIXUP_FDT_MEMORY is not set
 CONFIG_USE_BOOTCOMMAND=y
 CONFIG_BOOTCOMMAND="fdt addr ${fdtcontroladdr}; fdt move ${fdtcontroladdr} ${fdt_addr_r}; load mmc ${mmcdev}:${mmcpart} ${kernel_addr_r} ${image}; booti ${kernel_addr_r} - ${fdt_addr_r}; "
-# CONFIG_SPL_LEGACY_IMAGE_SUPPORT is not set
+# CONFIG_SPL_LEGACY_IMAGE_FORMAT is not set
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 # CONFIG_SPL_BANNER_PRINT is not set
 CONFIG_SPL_CPU=y