tcg: Pass TCGHelperInfo to tcg_gen_callN

In preparation for compiling tcg/ only once, eliminate
the all_helpers array.  Instantiate the info structs for
the generic helpers in accel/tcg/, and the structs for
the target-specific helpers in each translate.c.

Since we don't see all of the info structs at startup,
initialize at first use, using g_once_init_* to make
sure we don't race while doing so.

Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/qemu/typedefs.h

@@ -131,6 +131,7 @@ typedef struct ReservedRegion ReservedRegion;
 typedef struct SavedIOTLB SavedIOTLB;
 typedef struct SHPCDevice SHPCDevice;
 typedef struct SSIBus SSIBus;
+typedef struct TCGHelperInfo TCGHelperInfo;
 typedef struct TranslationBlock TranslationBlock;
 typedef struct VirtIODevice VirtIODevice;
 typedef struct Visitor Visitor;