x86: compile apm and voyager module only when selected in Kconfig

Previously the complete files were #ifdef'ed, but now handle that in the
Makefile.

May save a minor bit of compilation time.

[ Stephen Rothwell <sfr@canb.auug.org.au>: build dependency fix ]
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/boot/apm.c

@@ -19,8 +19,6 @@
 
 #include "boot.h"
 
-#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
-
 int query_apm_bios(void)
 {
 	u16 ax, bx, cx, dx, di;
@@ -95,4 +93,3 @@ int query_apm_bios(void)
 	return 0;
 }
 
-#endif