phy: xusb-tegra186: No redundant pad control

commit 12cc3812d2a680b27bab75a547c56fc265648748 from
https://nv-tegra.nvidia.com/r/3rdparty/canonical/linux-jammy.git jetson_36.3

BugLink: https://bugs.launchpad.net/bugs/2042935

Variable priv->bias_pad_enable records how many UTMI pads have been
powered off to decide whether to power down bias pad.

Below warning appears during suspend cycle when invalid value of that
variable is observed.

[] WARNING: at tegra186_utmi_pad_power_down+0x160/0x170
[] pc : tegra186_utmi_pad_power_down+0x160/0x170
[] lr : tegra186_utmi_pad_power_down+0xa0/0x170
:
[] Call trace:
[]  tegra186_utmi_pad_power_down+0x160/0x170
[]  tegra186_utmi_phy_power_off+0x10/0x30
[]  phy_power_off+0x48/0x100
[]  tegra_xusb_enter_elpg+0x204/0x500
[]  tegra_xusb_suspend+0x48/0x140
[]  platform_pm_suspend+0x2c/0xb0
[]  dpm_run_callback.isra.0+0x20/0xa0
[]  __device_suspend+0x118/0x330
[]  dpm_suspend+0x10c/0x1f0
[]  dpm_suspend_start+0x88/0xb0
[]  suspend_devices_and_enter+0x120/0x500
[]  pm_suspend+0x1ec/0x270

This patch is not to have redundant pad control for variable
priv->bias_pad_enable to be correctly counted in
tegra186_utmi_bias_pad_power_on()
tegra186_utmi_bias_pad_power_off()

, to add missing code to support below patch
xhci: tegra: USB2 pad power controls
Link: https://lore.kernel.org/r/20221111101813.32482-4-jilin@nvidia.com

http://nvbugs/4227704

Signed-off-by: Jim Lin <jilin@nvidia.com>
Reviewed-by: Haotien Hsu <haotienh@nvidia.com>
Reviewed-by: WK Tsai <wtsai@nvidia.com>
Tested-by: Kartik Rajput <kkartik@nvidia.com>
Reviewed-by: Kartik Rajput <kkartik@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Jacob Martin <jacob.martin@canonical.com>
Acked-by: Noah Wager <noah.wager@canonical.com>
Signed-off-by: Jacob Martin <jacob.martin@canonical.com>
Signed-off-by: Rajeshkumar Ramasamy <rajeshkumar.ramasamy@windriver.com>