linux: Clear up error message
Passing opt.device to perror() in do_open_file() results in confusing
error messages, as Jack reports,
Last night, I was trying to install syslinux (5.01) to a SD card of
mine, writing to a subdirectory to keep the layout neat:
syslinux-5.01/linux# ./syslinux -i -d /boot /dev/mmcblk0p1
/dev/mmcblk0p1: No such file or directory
The message is coming from do_open_file() in syslinux.c: the call to
open() fails because the containing directory isn't present, and then it
calls perror(opt.device).
We should instead be passing 'name' to perror() so that we know _which_
file doesn't exist.
Reported-by: Jack Kelly <jack@jackkelly.name>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>