accel/tcg: move softmmu_template.h to accel/tcg/

The header is only used by accel/tcg/cputlb.c so we can
move it to the accel/tcg/ folder, too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
[PMD: reword commit title to match series]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20170911213328.9701-2-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>