Commit 654102df2a ("kbuild: add generic support for built-in boot
DTBs") introduced generic support for built-in DTBs.
Select GENERIC_BUILTIN_DTB to use the generic rule.
To keep consistency across architectures, this commit also renames
CONFIG_ARC_BUILTIN_DTB_NAME to CONFIG_BUILTIN_DTB_NAME.
Now, "nsim_700" is the default value for CONFIG_BUILTIN_DTB_NAME, rather
than a fallback in case it is empty.
Acked-by: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>