RISC-V: kconfig.socs: convert usage of SOC_CANAAN to ARCH_CANAAN

While we cannot yet drop the SOC_ prefixed symbols, we can convert
uses of these symbols within Kconfig.socs to the ARCH_ variants.
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/Kconfig.socs

@@ -70,14 +70,14 @@ config SOC_CANAAN
 	help
 	  This enables support for Canaan Kendryte K210 SoC platform hardware.
 
-if SOC_CANAAN
+if ARCH_CANAAN
 
 config ARCH_CANAAN_K210_DTB_BUILTIN
 	def_bool SOC_CANAAN_K210_DTB_BUILTIN
 
 config SOC_CANAAN_K210_DTB_BUILTIN
 	bool "Builtin device tree for the Canaan Kendryte K210"
-	depends on SOC_CANAAN
+	depends on ARCH_CANAAN
 	default y
 	select OF
 	select BUILTIN_DTB
@@ -91,14 +91,14 @@ config ARCH_CANAAN_K210_DTB_SOURCE
 
 config SOC_CANAAN_K210_DTB_SOURCE
 	string "Source file for the Canaan Kendryte K210 builtin DTB"
-	depends on SOC_CANAAN
-	depends on SOC_CANAAN_K210_DTB_BUILTIN
+	depends on ARCH_CANAAN
+	depends on ARCH_CANAAN_K210_DTB_BUILTIN
 	default "k210_generic"
 	help
 	  Base name (without suffix, relative to arch/riscv/boot/dts/canaan)
 	  for the DTS file that will be used to produce the DTB linked into the
 	  kernel.
 
-endif # SOC_CANAAN
+endif # ARCH_CANAAN
 
 endmenu # "SoC selection"