platform: msm_shared: Check for RAM ptable init before fetching DDR size.
platform: msm_shared: Check for RAM ptable init before fetching DDR size.

Ensure RAM ptable is initialised before reading the DDR size.

CRs-Fixed: 684767
Change-Id: Ia17b769e62d99f3a447970419fc35b9b9bd50c1c

jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk,Foxda-Tech/argo8-bootable-bootloader-lk,jsr-d10/android_bootable_bootloader_lk,Foxda-Tech/argo8-bootable-bootloader-lk,Foxda-Tech/argo8-bootable-bootloader-lk,Foxda-Tech/argo8-bootable-bootloader-lk,Foxda-Tech/argo8-bootable-bootloader-lk,jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk