accel/tcg: Rename user-mode do_interrupt hack as fake_user_interrupt

accel/tcg: Rename user-mode do_interrupt hack as fake_user_interrupt

do_interrupt() is sysemu specific. However due to some X86
specific hack, it is also used in user-mode emulation, which
is why it couldn't be restricted to CONFIG_SOFTMMU (see the
comment around added in commit 78271684719: "cpu: tcg_ops:
move to tcg-cpu-ops.h, keep a pointer in CPUClass").
Keep the hack but rename the handler as fake_user_interrupt()
and restrict do_interrupt() to sysemu.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210911165434.531552-6-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>