tcg: Remove TCG_TARGET_HAS_{br,set}cond2 from riscv and loongarch64

tcg: Remove TCG_TARGET_HAS_{br,set}cond2 from riscv and loongarch64

These defines never should have been added as they were
never used.  Only 32-bit hosts may have these opcodes and
they have them unconditionally.

Fixes: 6cb14e4de29 ("tcg/loongarch64: Add the tcg-target.h file")
Fixes: fb1f70f3685 ("tcg/riscv: Add the tcg-target.h file")
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>