kernel: fix wrong detection of Linux-Testing-Version in makefile DUMP

kernel: fix wrong detection of Linux-Testing-Version in makefile DUMP

When the split was done, the case for testing kernel version wasn't
handled and only the to-be-compiled kernel version details files was
included. This cause the kernel Linux-Testing-Version output from
makefile target DUMP to report only the kernel version without the minor
version (example 6.1 instead of 6.1.29).

This value is expected with the full kernel version and this cause the
dump-target-info.pl script to not correctly identify if a target have a
testing kernel for the kernels calls.

Fix this regression by correctly including the kernel details files if
the target declare support for a testing kernel version.

Fixes: 0765466a42f4 ("kernel: split kernel version to dedicated files")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>