x86/kaslr: Drop redundant cur_entry from __process_mem_region()

cur_entry is only used as cur_entry.start + cur_entry.size, which is
always equal to end.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-7-nivedita@alum.mit.edu