scsi: megaraid_sas: Re-use max_mfi_cmds to calculate queue sizes

In megasas_init_adapter_fusion(), max_mfi_cmds is being calcuated as
(MEGASAS_FUSION_INTERNAL_CMDS + MEGASAS_FUSION_IOCTL_CMDS).  max_mfi_cmds
can be used in megasas_configure_queue_sizes.

Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>