selftests:x86: Fix Format String Warnings in lam.c

This commit addresses compiler warnings in lam.c related to the usage
of non-literal format strings without format arguments in the
'run_test' function.

Warnings fixed:
- Resolved warnings indicating that 'ksft_test_result_skip' and
'ksft_test_result' were called with 't->msg' as a format string without
accompanying format arguments.

Changes made:
- Modified the calls to 'ksft_test_result_skip' and 'ksft_test_result'
to explicitly include a format specifier ("%s") for 't->msg'.
- This ensures that the string is safely treated as a format argument,
adhering to safer coding practices and resolving the compiler warnings.

Signed-off-by: angquan yu <angquan21@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>