inject.f2fs: fix and cleanup parsing numeric options

This patch fixes:
  * parsing hex optarg of --idx option
  * converting -1 to 0xff...ff of --val option
and do a little cleanup of converting string to a long integer.

Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
1 file changed