USB: ice40: Add pm_qos requirements when uicc tranfers in progress

CPU enters idle power collapse numerous times during UICC transfers,
latency of CPU for coming out of power collapse is impacting UICC
throughput. Add pm_qos requirement to prevent CPU from going into
ideal power collapse mode when UICC transfers are in progress.

Also add a module parameter pm_qos delay to input period of the timer in
milliseconds that start after the last access of the hardware to de-vote
the DMA latency vote. Its value is interpreted in following manner
  pm_qos_delay = -1: Never vote for QOS
  pm_qos_delay = 0: Always vote for QOS
  pm_qos_delay > 0: delay before devote for QOS

Also add a debug facility to get current pm_qos_stats for UICC. The below
command needs to be executed to get these stats.

echo -n "pm_qos_stat" > /sys/kernel/debug/ice40_hcd/command

Change-Id: I629b7db07785a550b6fc7d938203a191a0783b9d
Signed-off-by: Tarun Gupta <tarung@codeaurora.org>