riscv: Unconditionnally select KASAN_VMALLOC if KASAN

If KASAN is enabled, VMAP_STACK depends on KASAN_VMALLOC so enable
KASAN_VMALLOC with KASAN so that we can enable VMAP_STACK by default.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230203075232.274282-7-alexghiti@rivosinc.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -117,6 +117,7 @@ config RISCV
 	select HAVE_RSEQ
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
+	select KASAN_VMALLOC if KASAN
 	select MODULES_USE_ELF_RELA if MODULES
 	select MODULE_SECTIONS if MODULES
 	select OF