x86: remove mach_apic.h, fix

Use apic_read() instead of open-coded mmio.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/include/asm/genapic.h

@@ -145,7 +145,7 @@ static inline unsigned int read_apic_id(void)
 {
 	unsigned int reg;
 
-	reg = *(u32 *)(APIC_BASE + APIC_ID);
+	reg = apic_read(APIC_ID);
 
 	return apic->get_apic_id(reg);
 }