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.

2 files changed, 13 insertions, 8 deletions

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index d842ab6..950819d 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,8 @@
+2020-06-03  Nelson Chu  <nelson.chu@sifive.com>
+
+	* riscv-opc.c (riscv_get_isa_spec_class): Change bfd_boolean to int.
+	(riscv_get_priv_spec_class): Likewise.
+
 2020-06-01  Alan Modra  <amodra@gmail.com>
 
 	* bpf-desc.c: Regenerate.
diff --git a/opcodes/riscv-opc.c b/opcodes/riscv-opc.c
index f011f1b..4481359 100644
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -958,24 +958,24 @@ static const struct isa_spec_t isa_specs[] =
 
 /* Get the corresponding ISA spec class by giving a ISA spec string.  */
 
-bfd_boolean
+int
 riscv_get_isa_spec_class (const char *s,
                          enum riscv_isa_spec_class *class)
 {
   const struct isa_spec_t *version;
 
   if (s == NULL)
-    return FALSE;
+    return 0;
 
   for (version = &isa_specs[0]; version->name != NULL; ++version)
     if (strcmp (version->name, s) == 0)
       {
        *class = version->class;
-       return TRUE;
+       return 1;
       }
 
   /* Can not find the supported ISA spec.  */
-  return FALSE;
+  return 0;
 }
 
 struct priv_spec_t
@@ -999,24 +999,24 @@ static const struct priv_spec_t priv_specs[] =
 /* Get the corresponding CSR version class by giving a privilege
    version string.  */
 
-bfd_boolean
+int
 riscv_get_priv_spec_class (const char *s,
                           enum riscv_priv_spec_class *class)
 {
   const struct priv_spec_t *version;
 
   if (s == NULL)
-    return FALSE;
+    return 0;
 
   for (version = &priv_specs[0]; version->name != NULL; ++version)
     if (strcmp (version->name, s) == 0)
       {
        *class = version->class;
-       return TRUE;
+       return 1;
       }
 
   /* Can not find the supported privilege version.  */
-  return FALSE;
+  return 0;
 }
 
 /* Get the corresponding privilege version string by giving a CSR