Convert socfpga: select CONFIG_HW_WATCHDOG support for ARCH_SOCFPGA

All Socfpga boards from ./include/configs/socfpga_* define
CONFIG_HW_WATCHDOG.
To ease CONFIG_HW_WATCHDOG conversion to Kconfig select it in
config ARCH_SOCFPGA (arch/arm/Kconfig) section.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Simon Goldschmidt <sgoldschmidt@de.pepperl-fuchs.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7b618d6..f6e43c6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -701,6 +701,7 @@
 	select DM_SPI_FLASH
 	select DM_SPI
 	select ENABLE_ARM_SOC_BOOT0_HOOK
+	select HW_WATCHDOG
 	select ARCH_EARLY_INIT_R
 	select ARCH_MISC_INIT
 	select SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION