riscv: gcov: enable gcov for RISC-V

This patch enables GCOV code coverage measurement on RISC-V.
Lightly tested on QEMU and Hifive Unleashed board, seems to work as
expected.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d8efbaa..a31169b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -64,6 +64,7 @@
 	select SPARSEMEM_STATIC if 32BIT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
+	select ARCH_HAS_GCOV_PROFILE_ALL
 
 config ARCH_MMAP_RND_BITS_MIN
 	default 18 if 64BIT