mlxsw: spectrum_cnt: Fix 64-bit division in mlxsw_sp_counter_resources_register

When building arm32 allyesconfig:

ld.lld: error: undefined symbol: __aeabi_uldivmod
>>> referenced by spectrum_cnt.c
>>>               net/ethernet/mellanox/mlxsw/spectrum_cnt.o:(mlxsw_sp_counter_resources_register) in archive drivers/built-in.a
>>> did you mean: __aeabi_uidivmod
>>> defined in: arch/arm/lib/lib.a(lib1funcs.o)

pool_size and bank_size are u64; use div64_u64 so that 32-bit platforms
do not error.

Fixes: ab8c4cc6 ("mlxsw: spectrum_cnt: Move config validation along with resource register")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>