RISC-V: Kconfig: fix spelling mistake "traget" -> "target"

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

arch/riscv/Kconfig

@@ -103,7 +103,7 @@ choice
 	prompt "Base ISA"
 	default ARCH_RV64I
 	help
-	  This selects the base ISA that this kernel will traget and must match
+	  This selects the base ISA that this kernel will target and must match
 	  the target platform.
 
 config ARCH_RV32I