usb: dwc3-msm: Fix warnings with pm_qos_update_request/remove_request

commit f0d6bd14 ("usb: dwc3-msm: Add dynamic pm_qos, clock and bus
voting in host mode") adding support for bus voting with PM_QOS_LATENCY.
With this change driver can call pm_qos_update_request or
pm_qos_remove_requests without adding the request and
printing warnings below.

pm_qos_update_request() called for unknown object
Modules linked in:
CPU: 2 PID: 406 Comm: kworker/2:2 Tainted: G W 3.18.31-gfbfce40-dirty #11
Workqueue: events dwc3_msm_otg_sm_work
Call trace:
[<ffffffc0000898a0>] dump_backtrace+0x0/0x270
[<ffffffc000089b24>] show_stack+0x14/0x1c
[<ffffffc000d81d90>] dump_stack+0x9c/0xd4
[<ffffffc0000a2cf8>] warn_slowpath_common+0x8c/0xb0
[<ffffffc0000a2d6c>] warn_slowpath_fmt+0x50/0x58
[<ffffffc0000eb32c>] pm_qos_update_request+0x34/0x5c
[<ffffffc0006a90ec>] dwc3_msm_perf_vote_update+0x19c/0x2b4
[<ffffffc0006abd90>] dwc3_otg_start_peripheral+0x1c0/0x204
[<ffffffc0006ad984>] dwc3_msm_otg_sm_work+0x590/0x878
[<ffffffc0000b8eb4>] process_one_work+0x260/0x450
[<ffffffc0000b9644>] worker_thread+0x2fc/0x418
[<ffffffc0000bd724>] kthread+0xe4/0xec
---[ end trace 9998738a22dac7cc ]---

Hence fix these warnings by adding proper check in driver for calling
pm_qos_update_request/pm_qos_remove_request.

Change-Id: I95cc2e68ce497cd2d11a4fbf783868076efb7359
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>