dahdi: Move 'timingslips' in with the other maintenance counters.

This allows timingslips to be reset along with the other counters and clarifies
the intended use.

This came up when Doug Bailey asked why he couldn't use dahdi_maint to clear
timing slips in addition to the other counters.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
dahdi: Trivial change of '__u32' -> 'u32' in struct dahdi_count.

struct dahdi_count is not directly exposed to user space, so we can use the
native u32 type instead of __u32 to clarify that.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
sysfs: Remove signed one-bit fields.

Eliminates the following warning from sparse:
  drivers/dahdi/dahdi-sysfs-chan.c:50:29: error: dubious one-bit signed bitfield

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
wct4xxp: t4_serial_setup() was called more often than necessary.

The driver iterates through all the spans on a given device during assignment,
checking for unassigned spans, but it was erroneously testing the span on which
assigned was called.

This just removes some unexpected behavior and provides a slight performance
increase on load and does not impact the functionality of the driver as far as
I'm aware.

Reported-by: Doug Bailey <dbailey@digium.com>
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Only use bus and no class for channel devices

It's wrong (and explicit oops with kernel >= 2.6.19) to set both
bus and class for the same device. But setting the class is not needed
in order to create a device. So just remove our dynamic devices from the
dahdi_class. It will only contain the fixed-named devices.

This fixes regression from cb4e4d006857d7fbc2ba51c63a96f2c97f2738d1.

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>