UBUNTU: [Config] Disable CONFIG_STUB_POULSBO

UBUNTU: [Config] Disable CONFIG_STUB_POULSBO

BugLink: http://bugs.launchpad.net/bugs/899244

There is a staging driver, psb_gfX (CONFIG_DRM_PSB), which supports
Intel GMA500 cards.  This driver has moved out of staging as of v3.3.
We currently have this staging driver enabled.  Unfortunately, this
driver conflicts with the poulsbo driver (CONFIG_STUB_POULSBO). The
poulsbo driver supports cards 8086:8108 and 8086:8109 both of which are
also supported by the psb_gfx driver.  It has been requested we disable
the poulsbo driver in favor of the psb_gfx driver.  Users owning 8086:8108
confirm they need to use the psb_gfx driver to have proper support.  If
they try to use the poulsbo driver, X fails.

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>