mmc: sdhci-s3c: Describe driver in KConfig

Describe better which driver applies to which SoC, to make configuring
kernel for Samsung SoC easier.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210924133257.112017-1-krzysztof.kozlowski@canonical.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -315,15 +315,17 @@ config MMC_SDHCI_TEGRA
 	  If unsure, say N.
 
 config MMC_SDHCI_S3C
-	tristate "SDHCI support on Samsung S3C SoC"
+	tristate "SDHCI support on Samsung S3C/S5P/Exynos SoC"
 	depends on MMC_SDHCI
 	depends on PLAT_SAMSUNG || ARCH_S5PV210 || ARCH_EXYNOS || COMPILE_TEST
 	help
 	  This selects the Secure Digital Host Controller Interface (SDHCI)
 	  often referrered to as the HSMMC block in some of the Samsung S3C
-	  range of SoC.
+	  (S3C2416, S3C2443, S3C6410), S5Pv210 and Exynos (Exynso4210,
+	  Exynos4412) SoCs.
 
-	  If you have a controller with this interface, say Y or M here.
+	  If you have a controller with this interface (thereforeyou build for
+	  such Samsung SoC), say Y or M here.
 
 	  If unsure, say N.