crypto: qat - fix spelling mistakes from 'bufer' to 'buffer'

Fix spelling mistakes from 'bufer' to 'buffer' in qat_common.
Also fix indentation issue caused by the spelling change.

Signed-off-by: Meadhbh Fitzpatrick <meadhbh.fitzpatrick@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>