Revert "serial: 8250, disable "too much work" messages"

This reverts commit f4f653e9.

Jiri writes:
	No, please drop this one. We need a better solution as it turned
	out that some boxes need 16k loops and it will increase with new
	processors :(.

Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Martin Pluskal <mpluskal@suse.com>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>