ipr: Inquiry IOA page 0xC4 during initialization.

Add an IOA Inquiry command for Page 0xC4 during IOA initialization to
collect cache capabilities, particularly to check if Sync IOA Write
Cache is supported.

Inquiry will happen right after Cap Inquiry on page 0xD0; and will
execute only if the "Supported Pages" field in Inquiry Page 0x0 shows
support for Page 0xC4.  Otherwise, assume Sync IOA Write Cache is
not supported.

Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>