qcacld-3.0: Avoid 64 bit division for 32bit targets compatibility

In function wlan_hdd_rx_rpm_mark_last_busy math division is performed
on unsingned 64bit integer. This leads to driver load failure on 32
bit machine targets. So avoid the math division for 64bit integer.

Change-Id: I967a0a64b421b47113821e1af5379cdd0125a34d
CRs-Fixed: 2576125