spl: dm: Kconfig: use more specific prereqs for SPL_REGMAP and SPL_SYSCON

SPL_REGMAP and SPL_SYSCON were marked as depending on DM, when a
stricter dependency of SPL_DM was possible.  This commit makes the
prereq more specific.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/core/Kconfig

@@ -97,7 +97,7 @@ config REGMAP
 
 config SPL_REGMAP
 	bool "Support register maps in SPL"
-	depends on DM
+	depends on SPL_DM
 	help
 	  Hardware peripherals tend to have one or more sets of registers
 	  which can be accessed to control the hardware. A register map
@@ -116,7 +116,7 @@ config SYSCON
 
 config SPL_SYSCON
 	bool "Support system controllers in SPL"
-	depends on REGMAP
+	depends on SPL_REGMAP
 	help
 	  Many SoCs have a number of system controllers which are dealt with
 	  as a group by a single driver. Some common functionality is provided