radeon/ac: make ac_shader_binary_config_start() available externally

The read config functions are different for r600 and radeonsi so
we can't just share the one in amd common. So just share this
instead.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/amd/common/ac_binary.c

@@ -188,7 +188,6 @@ void ac_elf_read(const char *elf_data, unsigned elf_size,
 	}
 }
 
-static
 const unsigned char *ac_shader_binary_config_start(
 	const struct ac_shader_binary *binary,
 	uint64_t symbol_offset)

src/amd/common/ac_binary.h

@@ -85,6 +85,14 @@ struct ac_shader_config {
 void ac_elf_read(const char *elf_data, unsigned elf_size,
 		 struct ac_shader_binary *binary);
 
+/**
+ * @returns A pointer to the start of the configuration information for
+ * the function starting at \p symbol_offset of the binary.
+ */
+const unsigned char *ac_shader_binary_config_start(
+	const struct ac_shader_binary *binary,
+	uint64_t symbol_offset);
+
 void ac_shader_binary_read_config(struct ac_shader_binary *binary,
 				  struct ac_shader_config *conf,
 				  unsigned symbol_offset,