tools: support binding to built-in kernel modules

tools: support binding to built-in kernel modules

Currently dpdk_nic_bind.py detects Linux kernel modules via reading
/proc/modules. Built-in ones aren't listed there and therefore they are
not being found by the script.

Add support for checking built-in modules with parsing the sysfs files.

This commit obsoletes the /proc/modules parsing approach.

Signed-off-by: Kamil Rytarowski <kamil.rytarowski@caviumnetworks.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>