common/rc: Add _sysfs_queue_path helper with partition support

Add a generic helper function to get the sysfs queue path for block
devices, properly handling partitions. Partitions don't have their own
queue directory in sysfs - they inherit from their parent device.

This helper checks if a device is a partition and returns the parent
device's queue path accordingly, making it easier to access queue
attributes for both whole disks and partitions.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>