[PATCH] suspend: Documentation update for IBM Thinkpad X30

As reported in Bugzilla Bug 6406, resume from S3 results in a blank screen.

For the IBM Thinkpad X30 using vesafb as the console driver, successful resume
from S3 requires option acpi_sleep=s3_bios,s3_mode.  Update documentation.

I would presume that, in any hardware, using vesafb as the console driver will
require as a minimum s3_mode.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: <igor47@uchicago.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>