The link support is no longer limited to the pseudo file system and now
covers both soft (symbolic) links and hard links across the VFS. Update
all references to the renamed configuration option PSEUDOFS_SOFTLINKS,
which has been renamed to FS_LINKS in the NuttX kernel, so that nshlib,
the interpreters, adb, tlpi and the test suites keep building.
This must be merged together with the corresponding NuttX change that
performs the actual kernel-side rename.
Signed-off-by: zhengyu16 <zhengyu16@xiaomi.com>