gen_compile_commands: add assembly files to compilation database

Like C source files, tooling can find it useful to have the assembly
source file compilation recorded.

The .S extension appears to used across all architectures.

Signed-off-by: Benjamin Gray <[e-mail]>
Reviewed-by: Fangrui Song <[e-mail]>
Reviewed-by: Nathan Chancellor <[e-mail]>
Reviewed-by: Nick Desaulniers <[e-mail]>
Signed-off-by: Masahiro Yamada <[e-mail]>

scripts/clang-tools/gen_compile_commands.py

···
 _DEFAULT_LOG_LEVEL = 'WARNING'
 
 _FILENAME_PATTERN = r'^\..*\.cmd$'
-_LINE_PATTERN = r'^savedcmd_[^ ]*\.o := (.* )([^ ]*\.c) *(;|$)'
+_LINE_PATTERN = r'^savedcmd_[^ ]*\.o := (.* )([^ ]*\.[cS]) *(;|$)'
 _VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
 # The tools/ directory adopts a different build system, and produces .cmd
 # files in a different format. Do not support it.