GPU-DRM-GMA500: Delete unnecessary checks before two function calls

The functions pci_dev_put() and psb_intel_i2c_destroy() test whether
their argument is NULL and then return immediately.
Thus the tests around their calls are not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/f1a0fd83-4320-f3db-e1bb-3b9832a4429f@users.sourceforge.net