KVM: selftests: Increase UCALL_MAX_ARGS to 7

Increase UCALL_MAX_ARGS to 7 to allow GUEST_ASSERT_4 to pass 3 builtin
ucall arguments specified in guest_assert_builtin_args plus 4
user-specified arguments.

Signed-off-by: Colton Lewis <[e-mail]>
Reviewed-by: Andrew Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Sean Christopherson <[e-mail]>

tools/testing/selftests/kvm/include/ucall_common.h

···
 	UCALL_UNHANDLED,
 };
 
-#define UCALL_MAX_ARGS 6
+#define UCALL_MAX_ARGS 7
 
 struct ucall {
 	uint64_t cmd;