staging: lustre: lclient: lcommon_cl.c fixing coding style issues

fixed: WARNING: line over 80 characters, used a new variable 'size_index' to
store the offset. Replaced "unsigned long" with  "loff_t" type for
'cur_index'. Removed the parenthesis around the second part of the if statement following the '||' as its not required.

Signed-off-by: Anil Belur <askb23@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>