KVM: arm64: Fix compile error due to sign extension

Use GENMASK() to generate the masks of device type and device id,
fixing compilation errors due to the sign extension when using
older versions of GCC (such as is 7.5):

In function ‘kvm_vm_ioctl_set_device_addr.isra.38’,
    inlined from ‘kvm_arch_vm_ioctl’ at arch/arm64/kvm/arm.c:1454:10:
././include/linux/compiler_types.h:354:38: error: call to ‘__compiletime_assert_599’ \
declared with attribute error: FIELD_GET: mask is not constant
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)

Fixes: 9f968c9 ("KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting")
Signed-off-by: Yang Yingliang <[email protected]>
[maz: tidy up commit message]
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Yang Yingliang

arch/arm64/include/uapi/asm/kvm.h

@@ -75,9 +75,11 @@ struct kvm_regs {
 
 /* KVM_ARM_SET_DEVICE_ADDR ioctl id encoding */
 #define KVM_ARM_DEVICE_TYPE_SHIFT	0
-#define KVM_ARM_DEVICE_TYPE_MASK	(0xffff << KVM_ARM_DEVICE_TYPE_SHIFT)
+#define KVM_ARM_DEVICE_TYPE_MASK	GENMASK(KVM_ARM_DEVICE_TYPE_SHIFT + 15, \
+						KVM_ARM_DEVICE_TYPE_SHIFT)
 #define KVM_ARM_DEVICE_ID_SHIFT		16
-#define KVM_ARM_DEVICE_ID_MASK		(0xffff << KVM_ARM_DEVICE_ID_SHIFT)
+#define KVM_ARM_DEVICE_ID_MASK		GENMASK(KVM_ARM_DEVICE_ID_SHIFT + 15, \
+						KVM_ARM_DEVICE_ID_SHIFT)
 
 /* Supported device IDs */
 #define KVM_ARM_DEVICE_VGIC_V2		0