Minor - move PORT_PS2_CTRLB from hw/ps2port.h to hw/timer.c

The PORT_PS2_CTRLB port is only used by timers - it's just a
historical artifact that it was part of the original ps2 controller.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/src/hw/ps2port.h b/src/hw/ps2port.h
index 566073a..e5d9014 100644
--- a/src/hw/ps2port.h
+++ b/src/hw/ps2port.h
@@ -5,7 +5,6 @@
 #include "types.h" // u8
 
 #define PORT_PS2_DATA          0x0060
-#define PORT_PS2_CTRLB         0x0061
 #define PORT_PS2_STATUS        0x0064
 
 // Standard commands.
diff --git a/src/hw/timer.c b/src/hw/timer.c
index 2832dec..5edc9fd 100644
--- a/src/hw/timer.c
+++ b/src/hw/timer.c
@@ -7,7 +7,6 @@
 #include "biosvar.h" // GET_LOW
 #include "config.h" // CONFIG_*
 #include "output.h" // dprintf
-#include "ps2port.h" // PORT_PS2_CTRLB
 #include "stacks.h" // yield
 #include "util.h" // timer_setup
 #include "x86.h" // cpuid
@@ -16,6 +15,7 @@
 #define PORT_PIT_COUNTER1      0x0041
 #define PORT_PIT_COUNTER2      0x0042
 #define PORT_PIT_MODE          0x0043
+#define PORT_PS2_CTRLB         0x0061
 
 // Bits for PORT_PIT_MODE
 #define PM_SEL_TIMER0   (0<<6)