arm64: Fix compilation errors while enabling memory hotplug

Fix compilation errors ecountered while enabling memory
hotplug caused by function prototype changes in
'commit 24e6d5a5 ("mm: pass the vmem_altmap
to arch_add_memory and __add_pages")'
'commit da024512 ("mm: pass the vmem_altmap
to arch_remove_memory and __remove_pages")'
'commit 24b6d416 ("mm: pass the vmem_altmap to vmemmap_free")'.
The errors were caused since the prototype changes in functions
vmemmap_free arch_remove_memory and arch_add_memory were not propagated
to the arm64 version.

Change-Id: I9933ab14d6483f8a6c8ddc7fe9b414149e9df3b7
Signed-off-by: Swathi Sridhar <swatsrid@codeaurora.org>