ARM: dts: AM4372: add few nodes

Populate uarts, timers, rtc, wdt, gpio, i2c, spi, cpsw & pwm nodes.

Reason for adding these nodes early - hwmod code required address
space of peripherals corresponding to these nodes (as address space
details are removed from hwmod database).

uart0, timers - 1 & 2 and synctimer were already present, so here the
remaining uarts & timers are added.

All properties as per the existing binding has been added for uart,
timer, rtc, wdt & gpio. Even though that was not the current scope
of work, felt adding those would reduce or require no effort later
to get these peripherals working.

For i2c, spi, cpsw & pwm - only the properties that were sure to be
correct has been added (main intention is to make hwmod happy and
avoid any later modification to here added properties).

While at it add "ti,hwmod" property to already existing nodes.

Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Benoit Cousson <bcousson@baylibre.com>