crypto: qat - add sysfs_added flag for ras

The qat_ras 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_ras 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_ras' not found for kobject '0000:6b:00.0'
    ...
    sysfs_remove_groups+0x29/0x50
    adf_sysfs_stop_ras+0x4b/0x80 [intel_qat]
    adf_dev_stop+0x43/0x1d0 [intel_qat]
    adf_dev_down+0x4b/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: 532d7f6b ("crypto: qat - add error counters")
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>