ipr: Fix regression when loading firmware

ipr: Fix regression when loading firmware

Commit d63c7dd5bcb9 ("ipr: Fix out-of-bounds null overwrite") removed
the end of line handling when storing the update_fw sysfs attribute.
This changed the userpace API because it started refusing writes
terminated by a line feed, which broke the update tools we already have.

This patch re-adds that handling, so both a write terminated by a line
feed or not can make it through with the update.

Fixes: d63c7dd5bcb9 ("ipr: Fix out-of-bounds null overwrite")
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>
Cc: Insu Yun <[email protected]>
Acked-by: Brian King <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>