tests: fix uClibc for getversion.c

This patch fixes compilation with uClibc by applying the same fallback
as commit e12d761 to the `getversion.c`
file, which was previously overlooked.
 
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: José Luis Salvador Rufo <salvador.joseluis@gmail.com>
Closes openzfs#16735
Closes openzfs#16741

tests/zfs-tests/cmd/getversion.c

@@ -19,9 +19,13 @@
  */
 
 #include <sys/ioctl.h>
+#ifdef _KERNEL
+#include <sys/fcntl.h>
+#else
+#include <fcntl.h>
+#endif
 #include <linux/fs.h>
 #include <err.h>
-#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>