kvm: selftests: Fix spelling mistake "missmatch" -> "mismatch"

There is a spelling mistake in an error message. Fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Message-Id: <20210826120752.12633-1-colin.king@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/sparsebit.c

@@ -1866,7 +1866,7 @@ void sparsebit_validate_internal(struct sparsebit *s)
 		 * of total bits set.
 		 */
 		if (s->num_set != total_bits_set) {
-			fprintf(stderr, "Number of bits set missmatch,\n"
+			fprintf(stderr, "Number of bits set mismatch,\n"
 				"  s->num_set: 0x%lx total_bits_set: 0x%lx",
 				s->num_set, total_bits_set);