[SCSI] ufs: fix the setting interrupt aggregation counter

IACTH(Interrupt aggregation counter threshold) value is allowed
up to 0x1F and current setting value is the maximum.
This value is related with NUTRS(max:0x20) of HCI's capability.
Considering HCI controller doesn't support the maximum, IACTH
setting should be adjusted with possible value.
For that, existing 'ufshcd_config_int_aggr' is split into two part
[reset, configure].

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Tested-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Santosh Y <santoshsy@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>