x86: Use 'unsigned int' in install_e820_map() functions

This fixes the following checkpatch warning:

  warning: Prefer 'unsigned int' to bare use of 'unsigned'

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
index 351f021..8355c34 100644
--- a/arch/x86/include/asm/e820.h
+++ b/arch/x86/include/asm/e820.h
@@ -24,6 +24,7 @@
 #endif /* __ASSEMBLY__ */
 
 /* Implementation defined function to install an e820 map */
-unsigned install_e820_map(unsigned max_entries, struct e820entry *);
+unsigned int install_e820_map(unsigned int max_entries,
+			      struct e820entry *);
 
 #endif /* _ASM_X86_E820_H */