x86/alternatives: Fix build warning

Fixes these warnings:

 arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
 arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast

Caused by:

  2cfa1978: ftrace/alternatives: Introducing *_text_reserved functions

Changes in v2:
  - Use local variables to compare, instead of type casts.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100205171647.15750.37221.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/alternative.c

@@ -395,12 +395,14 @@ int alternatives_text_reserved(void *start, void *end)
 {
 	struct smp_alt_module *mod;
 	u8 **ptr;
+	u8 *text_start = start;
+	u8 *text_end = end;
 
 	list_for_each_entry(mod, &smp_alt_modules, next) {
-		if (mod->text > end || mod->text_end < start)
+		if (mod->text > text_end || mod->text_end < text_start)
 			continue;
 		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
-			if (start <= *ptr && end >= *ptr)
+			if (text_start <= *ptr && text_end >= *ptr)
 				return 1;
 	}