[PATCH] Fix some compilation warnings on x86 system

Fix the following warnings:

  makedumpfile.c: In function ‘__exclude_unnecessary_pages’:
  makedumpfile.c:5923: warning: cast from pointer to integer of different size
  makedumpfile.c:5929: warning: cast to pointer from integer of different size
  makedumpfile.c:5932: warning: cast to pointer from integer of different size
  makedumpfile.c:5944: warning: cast to pointer from integer of different size
  makedumpfile.c:5948: warning: cast to pointer from integer of different size
  makedumpfile.c:5951: warning: cast to pointer from integer of different size
  makedumpfile.c: In function ‘find_unused_vmemmap_pages’:
  makedumpfile.c:6336: warning: integer constant is too large for ‘unsigned long’ type
  makedumpfile.c: In function ‘kdump_thread_function_cyclic’:
  makedumpfile.c:7873: warning: initialization from incompatible pointer type

Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>