memshare: Skip collecting elf for failed hypervisor unmapping memory

Prevent collecting ramdump for memory region which have failed to
hypervisor unmap by continuing through the loop and with proper
checks for successful hypervisor mapping.

Change-Id: Ied3e5c840cbf66170cfbcf09eecd6130dd34bd6c
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>