platform: msm_shared: assert if buffer is not NULL
platform: msm_shared: assert if buffer is not NULL

Check if it is not successfully malloced the buffer.

CRs-Fixed: 687723
Change-Id: I4749c4f37caaa85dcc1e387305bdfe2f1c2e409b

CanarySolutions/little-kernel,Foxda-Tech/polaris-bootable-bootloader-lk,M1cha/lktris,M1cha/lktris,CanarySolutions/little-kernel,CanarySolutions/little-kernel,efidroid/lk,Foxda-Tech/polaris-bootable-bootloader-lk,M1cha/lktris,CanarySolutions/little-kernel,Foxda-Tech/polaris-bootable-bootloader-lk,efidroid/lk,efidroid/lk,M1cha/lktris,CanarySolutions/little-kernel,efidroid/lk,efidroid/lk,Foxda-Tech/polaris-bootable-bootloader-lk,M1cha/lktris,Foxda-Tech/polaris-bootable-bootloader-lk