msm: kgsl: Treat 0x0 as valid GPU pagetable physical address

Iommu driver could be allocating a valid GPU pagetable at
physical address 0x0, remove assumption from GPU kernel driver
that 0x0 is invalid pagetable address.

Change-Id: I213c0fbc1d90a13bef83c7d7589ad9e5729771fd
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: kgsl: Fix mem leak when page allocation fails

Page allocation may fail during OOM condition. Update
sglen and size to correct value (allocated) so that
they get freed in kgsl_sharedmem_free().

Change-Id: I1aa0ca77bb767523dfcf0f6cc3a21eac2b6b80e4
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>