riscv: Avoid kgdb.h including gdb_xml.h to solve unused-const-variable warning

The constant arrays in gdb_xml.h are only used in arch/riscv/kernel/kgdb.c,
but other c files may include the gdb_xml.h indirectly via including the
kgdb.h. Hence, It will cause many unused-const-variable warnings. This
patch makes the kgdb.h not to include the gdb_xml.h to solve this problem.

Signed-off-by: Vincent Chen <[e-mail]>
Signed-off-by: Palmer Dabbelt <[e-mail]>

arch/riscv/include/asm/gdb_xml.h

···
 #ifndef __ASM_GDB_XML_H_
 #define __ASM_GDB_XML_H_
 
-#define kgdb_arch_gdb_stub_feature riscv_gdb_stub_feature
-static const char riscv_gdb_stub_feature[64] =
+const char riscv_gdb_stub_feature[64] =
 			"PacketSize=800;qXfer:features:read+;";
 
 static const char gdb_xfer_read_target[31] = "qXfer:features:read:target.xml:";

arch/riscv/include/asm/kgdb.h

···
 #define DBG_REG_BADADDR_OFF 34
 #define DBG_REG_CAUSE_OFF 35
 
-#include <asm/gdb_xml.h>
+extern const char riscv_gdb_stub_feature[64];
+
+#define kgdb_arch_gdb_stub_feature riscv_gdb_stub_feature
 
 #endif
 #endif