dpaa2-eth: Use proper division helper in dpaa2_dbg_ch_show

When building arm32 allmodconfig:

ERROR: modpost: "__aeabi_uldivmod"
[drivers/net/ethernet/freescale/dpaa2/fsl-dpaa2-eth.ko] undefined!

frames and cdan are both of type __u64 (unsigned long long) so we need
to use div64_u64 to avoid this issues.

Fixes: 460fd830 ("dpaa2-eth: add channel stat to debugfs")
Link: https://github.com/ClangBuiltLinux/linux/issues/1012


Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: kernelci.org bot <bot@kernelci.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>