staging: lustre: fid: Change positional struct initializers to C99
This patch makes no functional changes. Struct initializers in the
fid directory that use C89 or GCC-only syntax are updated to C99
syntax.
The C99 syntax prevents incorrect initialization if values are
accidently placed in the wrong position, allows changes in the struct
definition, and clears any members that are not given an explicit
value.
The following struct initializers have been updated: