compat: do not backport ktime_get_coarse_boottime_ns to c8s

Also bump the c8s version stamp.

Reported-by: Vladimír Beneš <vbenes@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff --git a/src/compat/compat.h b/src/compat/compat.h
index d166ac2..aebeabf 100644
--- a/src/compat/compat.h
+++ b/src/compat/compat.h
@@ -16,7 +16,7 @@
 #define ISRHEL7
 #elif RHEL_MAJOR == 8
 #define ISRHEL8
-#if RHEL_MINOR >= 6
+#if RHEL_MINOR >= 7
 #define ISCENTOS8S
 #endif
 #endif
@@ -390,7 +390,7 @@
 #define system_power_efficient_wq system_unbound_wq
 #endif
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 3, 0)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 3, 0) && !defined(ISCENTOS8S)
 #include <linux/ktime.h>
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
 #include <linux/hrtimer.h>