x86: re-enable OPTIMIZE_INLINING

re-enable OPTIMIZE_INLINING more widely. Jeff Dike fixed the remaining
outstanding issue in this commit:

| commit 4f81c535
| Author: Jeff Dike <jdike@addtoit.com>
| Date:   Mon Jul 7 13:36:56 2008 -0400
|
|     [UML] fix gcc ICEs and unresolved externs
[...]
|    This patch reintroduces unit-at-a-time for gcc >= 4.0, bringing back the
|    possibility of Uli's crash.  If that happens, we'll debug it.

it's still default-off and thus opt-in.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig.debug

@@ -287,7 +287,6 @@ config CPA_DEBUG
 
 config OPTIMIZE_INLINING
 	bool "Allow gcc to uninline functions marked 'inline'"
-	depends on BROKEN
 	help
 	  This option determines if the kernel forces gcc to inline the functions
 	  developers have marked 'inline'. Doing so takes away freedom from gcc to
@@ -298,5 +297,7 @@ config OPTIMIZE_INLINING
 	  become the default in the future, until then this option is there to
 	  test gcc for this.
 
+	  If unsure, say N.
+
 endmenu