radeon/llvm: Initialize gallivm targets when initializing the AMDGPU target v2

This fixes a race condition in the glx-multithreaded-shader-compile
test.

v2:
  - Replace gallivm_init_llvm_{begin,end}() with gallivm_init_llvm_targets().

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

CC: "10.6 11.0" <mesa-stable@lists.freedesktop.org>

src/gallium/drivers/radeon/radeon_llvm_emit.c

@@ -26,6 +26,7 @@
 #include "radeon_llvm_emit.h"
 #include "radeon_elf_util.h"
 #include "c11/threads.h"
+#include "gallivm/lp_bld_misc.h"
 #include "util/u_memory.h"
 #include "pipe/p_shader_tokens.h"
 
@@ -87,6 +88,7 @@ void radeon_llvm_shader_type(LLVMValueRef F, unsigned type)
 
 static void init_r600_target()
 {
+	gallivm_init_llvm_targets();
 #if HAVE_LLVM < 0x0307
 	LLVMInitializeR600TargetInfo();
 	LLVMInitializeR600Target();