cmd: Convert existing long help messages to the new macro

- Generally we just drop the #ifdef CONFIG_SYS_LONGHELP and endif lines
  and use U_BOOT_LONGHELP to declare the same variable name as before
- In a few places, either rename the variable to follow convention or
  introduce the variable as it was being done inline before.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/cpu.c b/cmd/cpu.c
index 3148524..245a82f 100644
--- a/cmd/cpu.c
+++ b/cmd/cpu.c
@@ -83,12 +83,9 @@
 	return 0;
 }
 
-#if IS_ENABLED(CONFIG_SYS_LONGHELP)
-static char cpu_help_text[] =
+U_BOOT_LONGHELP(cpu,
 	"list	- list available CPUs\n"
-	"cpu detail	- show CPU detail"
-	;
-#endif
+	"cpu detail	- show CPU detail");
 
 U_BOOT_CMD_WITH_SUBCMDS(cpu, "display information about CPUs", cpu_help_text,
 	U_BOOT_SUBCMD_MKENT(list, 1, 1, do_cpu_list),