crypto: qat - add sysfs_added flag for rate limiting

The qat_rl sysfs attribute group is registered within the adf_dev_start()
function, alongside other driver components.
If any of the functions preceding the group registration fails,
the adf_dev_start() function returns, and the caller, to undo the
operation, invokes adf_dev_stop() followed by adf_dev_shutdown().
However, the current flow lacks information about whether the
registration of the qat_rl attribute group was successful or not.

In cases where this condition is encountered, an error similar to
the following might be reported:

4xxx 0000:6b:00.0: Starting device qat_dev0
4xxx 0000:6b:00.0: qat_dev0 started 9 acceleration engines
4xxx 0000:6b:00.0: Failed to send init message
4xxx 0000:6b:00.0: Failed to start device qat_dev0
sysfs group 'qat_rl' not found for kobject '0000:6b:00.0'
...
sysfs_remove_groups+0x2d/0x50
adf_sysfs_rl_rm+0x44/0x70 [intel_qat]
adf_rl_stop+0x2d/0xb0 [intel_qat]
adf_dev_stop+0x33/0x1d0 [intel_qat]
adf_dev_down+0xf1/0x150 [intel_qat]
...
4xxx 0000:6b:00.0: qat_dev0 stopped 9 acceleration engines
4xxx 0000:6b:00.0: Resetting device qat_dev0

To prevent attempting to remove attributes from a group that has not
been added yet, a flag named 'sysfs_added' is introduced. This flag
is set to true upon the successful registration of the attribute group.

Fixes: d9fb8408376e ("crypto: qat - add rate limiting feature to qat_4xxx")
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Ahsan Atta <ahsan.atta@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - add rate limiting sysfs interface

Add an interface for the rate limiting feature which allows to add,
remove and modify a QAT SLA (Service Level Agreement).

This adds a new sysfs attribute group, `qat_rl`, which can be accessed
from /sys/bus/pci/devices/<BUS:DEV:FUNCTION> with the following
hierarchy:
|-+ qat_rl
|---- id (RW) # SLA identifier
|---- cir (RW) # Committed Information Rate
|---- pir (RW) # Peak Information Rate
|---- srv (RW) # Service to be rate limited
|---- rp (RW) (HEX) # Ring pairs to be rate limited
|---- cap_rem (RW) # Remaining capability for a service
|---- sla_op (WO) # Allows to perform an operation on an SLA

The API works by setting the appropriate RW attributes and then
issuing a command through the `sla_op`. For example, to create an SLA, a
user needs to input the necessary data into the attributes cir, pir, srv
and rp and then write into `sla_op` the command `add` to execute the
operation.
The API also provides `cap_rem` attribute to get information about
the remaining device capability within a certain service which is
required when setting an SLA.

Signed-off-by: Ciunas Bennett <ciunas.bennett@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>