RISC-V: Fix the error when building RISC-V linux native gdbserver.

The original report is as follow,
https://sourceware.org/pipermail/binutils/2020-June/111383.html

Inlcude the bfd.h in the include/opcode/riscv.h may cause gdbserver fail
to build.  I just want to use the `bfd_boolean` in the opcodes/riscv-opc.c,
but I didn't realize this cause the build failed.  Fortunately, I can also
use the `int` as the function return types just like others in the
opcodes/riscv-opc.c.

	include/
	* opcode/riscv.h: Remove #include "bfd.h".  And change the return
	types of riscv_get_isa_spec_class and riscv_get_priv_spec_class
	from bfd_boolean to int.

	opcodes/
	* riscv-opc.c (riscv_get_isa_spec_class): Change bfd_boolean to int.
	(riscv_get_priv_spec_class): Likewise.

1 files changed, 2 insertions, 3 deletions

diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index feeaa6e..fecf410 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -24,7 +24,6 @@
 #include "riscv-opc.h"
 #include <stdlib.h>
 #include <stdint.h>
-#include "bfd.h"
 
 typedef uint64_t insn_t;
 
@@ -490,9 +489,9 @@ extern const struct riscv_opcode riscv_opcodes[];
 extern const struct riscv_opcode riscv_insn_types[];
 extern const struct riscv_ext_version riscv_ext_version_table[];
 
-extern bfd_boolean
+extern int
 riscv_get_isa_spec_class (const char *, enum riscv_isa_spec_class *);
-extern bfd_boolean
+extern int
 riscv_get_priv_spec_class (const char *, enum riscv_priv_spec_class *);
 extern const char *
 riscv_get_priv_spec_name (enum riscv_priv_spec_class);