jfs: le*_add_cpu conversion

replace all:
little_endian_variable = cpu_to_leX(leX_to_cpu(little_endian_variable) +
                                        expression_in_cpu_byteorder);
with:
        leX_add_cpu(&little_endian_variable, expression_in_cpu_byteorder);
generated with semantic patch

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: jfs-discussion@lists.sourceforge.net