KVM: selftests: Remove unused macro in the hardware disable test

The macro GUEST_CODE_PIO_PORT is never referenced in the code,
just remove it.

Signed-off-by: Ba Jing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Sean Christopherson <[e-mail]>

tools/testing/selftests/kvm/hardware_disable_test.c

···
 #define SLEEPING_THREAD_NUM (1 << 4)
 #define FORK_NUM (1ULL << 9)
 #define DELAY_US_MAX 2000
-#define GUEST_CODE_PIO_PORT 4
 
 sem_t *sem;