[RFC] doc: update required kernel version to 4.14

[Stephen Hemminger]

The 4.4 kernel was end of life in February 2022,
and the next LTS is 4.9 and it is reaching EOL in January 2023.
The main distro using 4.9 is Debian Stretch and it is no longer
supported. When DPDK 22.11 is released, the 4.9 kernel would
only be receiving fixes for three months; therefore
lets make the official version 4.14.

As always, current major enterprise Linux releases will continue
to be supported, but those releases don't track regular kernel
version numbering.

For full details on kernel support see:
https://www.kernel.org/category/releases.html
https://en.wikipedia.org/wiki/Linux_kernel_version_history

Debian Stretch:
https://www.debian.org/releases/stretch/

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 doc/guides/linux_gsg/sys_reqs.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/guides/linux_gsg/sys_reqs.rst b/doc/guides/linux_gsg/sys_reqs.rst
index 08d45898f025..ed22b6e80b4c 100644
--- a/doc/guides/linux_gsg/sys_reqs.rst
+++ b/doc/guides/linux_gsg/sys_reqs.rst
@@ -105,7 +105,7 @@ System Software
 
 **Required:**
 
-*   Kernel version >= 4.4
+*   Kernel version >= 4.14
 
     The kernel version required is based on the oldest long term stable kernel available
     at kernel.org when the DPDK version is in development.
-- 
2.35.1