bionic: Change the type of soinfo's size to size_t

Some system functions like munmap expect soinfo's size to be size_t, but currently
it is unsigned. Change it to size_t to fit 64bit's portability.

Change-Id: I0bf6d522b38b0cd9bf1db05b004b5326217412a2
Signed-off-by: Weiwu Chen <weiwu.chen@intel.com>
Signed-off-by: Qiming Shi <qiming.shi@intel.com>
diff --git a/linker/linker.h b/linker/linker.h
index 67a86ab..972050f 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -106,7 +106,7 @@
   size_t phnum;
   Elf_Addr entry;
   Elf_Addr base;
-  unsigned size;
+  size_t size;
 
 #ifndef __LP64__
   uint32_t unused1;  // DO NOT USE, maintained for compatibility.