riscv: Select required drivers for Kendryte SOC

This patch selects drivers required for the Kendryte K210 SOC.
Since K210 SoC based boards do not provide a device tree, this patch
also enables the BUILTIN_DTB option.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/Kconfig.socs

@@ -37,6 +37,10 @@ config SOC_VIRT
 config SOC_KENDRYTE
 	bool "Kendryte K210 SoC"
 	depends on !MMU
+	select BUILTIN_DTB
+	select SERIAL_SIFIVE if TTY
+	select SERIAL_SIFIVE_CONSOLE if TTY
+	select SIFIVE_PLIC
 	help
 	  This enables support for Kendryte K210 SoC platform hardware.