dm: core: Make SPL_DM_SEQ_ALIAS select SPL_STRTO

Enabling CONFIG_DM_SEQ_ALIAS enables code which relies on
`trailing_strtol()` - which is only linked in SPL when CONFIG_SPL_STRTO
is enabled.

CONFIG_SPL_STRTO is not enabled by default - to ensure this function is
available in SPL, CONFIG_SPL_DM_SEQ_ALIAS should select
CONFIG_SPL_STRTO.

Signed-off-by: Oliver Gaskell <Oliver.Gaskell@analog.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 1a7be4d..c39abe3 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -146,6 +146,7 @@
 config SPL_DM_SEQ_ALIAS
 	bool "Support numbered aliases in device tree in SPL"
 	depends on SPL_DM
+	select SPL_STRTO
 	help
 	  Most boards will have a '/aliases' node containing the path to
 	  numbered devices (e.g. serial0 = &serial0). This feature can be