common: Convert the U-Boot commands to LG-arrays

This patch converts the old method of creating a list of command
onto the new LG-arrays code. The old u_boot_cmd section is converted
to new u_boot_list_cmd subsection and LG-array macros used as needed.

Minor adjustments had to be made to the common code to work with the
LG-array macros, mostly the fixup_cmdtable() calls are now passed the
ll_entry_start and ll_entry_count instead of linker-generated symbols.

The command.c had to be adjusted as well so it would use the newly
introduced LG-array API instead of directly using linker-generated
symbols.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/nds32/lib/board.c b/arch/nds32/lib/board.c
index 875f220..91395ca 100644
--- a/arch/nds32/lib/board.c
+++ b/arch/nds32/lib/board.c
@@ -320,8 +320,8 @@
 	/*
 	 * We have to relocate the command table manually
 	 */
-	fixup_cmdtable(&__u_boot_cmd_start,
-		(ulong)(&__u_boot_cmd_end - &__u_boot_cmd_start));
+	fixup_cmdtable(ll_entry_start(cmd_tbl_t, cmd),
+			ll_entry_count(cmd_tbl_t, cmd));
 #endif /* defined(CONFIG_NEEDS_MANUAL_RELOC) */
 
 	serial_initialize();