LU-6142 fld: Fix style issues for fld_cache.c

LU-6142 fld: Fix style issues for fld_cache.c

This patch fixes issues reported by checkpatch
for file lustre/fld/fld_cache.c

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Change-Id: I91377fca9437fa31091ca039afba8f0c2ad8da7b
Reviewed-on: https://review.whamcloud.com/39205
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Ben Evans <beevans@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>