basic: update CIFS magic
Kernel commit
dea2903719283c156b53741126228c4a1b40440f exposed (and
renamed) CIFS_MAGIC_NUMBER as CIFS_SUPER_MAGIC along with
SMB2_SUPER_MAGIC.
This fixes the following build fail on current Fedora Rawhide:
```
../src/basic/meson.build:389:8: ERROR: Problem encountered: found unknown filesystem(s) defined in kernel headers:
Filesystem found in kernel header but not in filesystems-gperf.gperf: CIFS_SUPER_MAGIC
Filesystem found in kernel header but not in filesystems-gperf.gperf: SMB2_SUPER_MAGIC
```