fs/jffs2/jffs2_1pass.c: fix warning: variable ... set but not used

Fix:
jffs2_1pass.c: In function 'jffs2_1pass_read_inode':
jffs2_1pass.c:699:7: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
jffs2_1pass.c: In function 'jffs2_1pass_build_lists':
jffs2_1pass.c:1578:14: warning: variable 'empty_start' set but not used [-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>