fs:ext4:write: Add lldiv and do_div to perform 64-32 bits division

The ext4write code has been using direct calls to 64-32 division
(/ and %).

Officially supported u-boot toolchains (eldk-5.[12].x) generate calls
to __aeabi_uldivmod(), which is niether defined in the toolchain libs
nor u-boot source tree.

Due to that, when the ext4write command has been executed, "undefined
instruction" execption was generated (since the __aeabi_uldivmod()
is not provided).

To fix this error, lldiv() for division and do_div() for modulo have
been used.

Those two functions are recommended for performing 64-32 bit number
division in u-boot.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>