cmd: misc: Disable by default on sunXi

The sunXi arm64 build has overflown, leading to the main U-boot binary
overwriting the environment when flashing the new image, or even worse,
overwriting itself when we're calling saveenv.

Disable this command that is not critical until we can adress the issue
properly.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

cmd/Kconfig

@@ -1138,6 +1138,7 @@ config CMD_GETTIME
 # TODO: rename to CMD_SLEEP
 config CMD_MISC
 	bool "sleep"
+	default n if ARCH_SUNXI
 	default y
 	help
 	  Delay execution for some time