This commit is a preparation for enabling XUSB SC7 support.
It rearranges Tegra210 XUSB PADCTL UPHY initialization sequence,
for the following reasons:

1. PLLE hardware power sequencer has to be enabled only after both
   PEX UPHY PLL and SATA UPHY PLL are initialized.
   tegra210_uphy_init() -> tegra210_pex_uphy_enable()
                        -> tegra210_sata_uphy_enable()
                        -> tegra210_plle_hw_sequence_start()
                        -> tegra210_aux_mux_lp0_clamp_disable()

2. At cold boot and SC7 exit, the following bits must be cleared after
   PEX/SATA lanes are out of IDDQ (IDDQ_DISABLE=1).
   a. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN,
   b. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN_EARLY
   c. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_VCORE_DOWN

   tegra210_pex_uphy_enable() and tegra210_sata_uphy_enable() are in
   charge of bringing lanes out of IDDQ, and then AUX_MUX_LP0_* bits
   will be cleared by tegra210_aux_mux_lp0_clamp_disable().

3. Once UPHY PLL hardware power sequencer is enabled, do not assert
   reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken.
Signed-off-by: JC Kuo <jckuo@nvidia.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>