usb: dwc3-am62: fix module unload/reload behavior

usb: dwc3-am62: fix module unload/reload behavior

As runtime PM is enabled, the module can be runtime
suspended when .remove() is called.

Do a pm_runtime_get_sync() to make sure module is active
before doing any register operations.

Doing a pm_runtime_put_sync() should disable the refclk
so no need to disable it again.

Fixes the below warning at module removel.

[   39.705310] ------------[ cut here ]------------
[   39.710004] clk:162:3 already disabled
[   39.713941] WARNING: CPU: 0 PID: 921 at drivers/clk/clk.c:1090 clk_core_disable+0xb0/0xb8

We called of_platform_populate() in .probe() so call the
cleanup function of_platform_depopulate() in .remove().
Get rid of the now unnnecessary dwc3_ti_remove_core().
Without this, module re-load doesn't work properly.

Fixes: e8784c0aec03 ("drivers: usb: dwc3: Add AM62 USB wrapper driver")
Cc: stable@vger.kernel.org # v5.19+
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20240227-for-v6-9-am62-usb-errata-3-0-v4-1-0ada8ddb0767@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>