src/cpu: Capitalize CPU, APIC and IOAPIC typo fix

Change-Id: I82e0736dc6b44cfcc57cdfdc786c85c4b6882260
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/16276
Tested-by: build bot (Jenkins)
Reviewed-by: Omar Pakker

src/cpu/x86/16bit/entry16.inc

@@ -79,7 +79,7 @@ _start16bit:
 	 *
 	 * The criteria for relocation have been relaxed to their
 	 * utmost, so that we can use the same code for both
-	 * our initial entry point and startup of the second cpu.
+	 * our initial entry point and startup of the second CPU.
 	 * The code assumes when executing at _start16bit that:
 	 * (((cs & 0xfff) == 0) and (ip == _start16bit & 0xffff))
 	 * or