This build option has been deprecated since 8.0.
Remove all CONFIG_GPROF code that depends on that,
including one errant check using TARGET_GPROF.

Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>