selftests: kselftest: fix wrong test number in ksft_exit_skip

selftests: kselftest: fix wrong test number in ksft_exit_skip

ksft_exit_skip() increments ksft_xskip before printing the KTAP
result. As a result, ksft_test_num() already includes the skipped
test.

Adding 1 to ksft_test_num() increments the printed test number
again, producing an incorrect test number and wrong KTAP output.

Drop the extra increment and print ksft_test_num() directly.

Link: https://lore.kernel.org/r/20260427112447.147985-1-sarthak.sharma@arm.com
Fixes: b85d387c9b09 ("kselftest: fix TAP output for skipped tests")
Signed-off-by: Sarthak Sharma <sarthak.sharma@arm.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>