[SCSI] megaraid_sas: fixes for few endianess issues

Fixed two issues in this patch-
1) In function megasas_get_pd_list(), data read(pd_addr->deviceId) from DMAed memory is converted to CPU's endianess.
2) While register AEN, removed some endianness conversion on some fields, since their endianess is already converted.

Signed-off-by: Sumit Saxena <sumit.saxena@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>