soc: ti: Add Support for the TI Page-based Address Translator (PAT)

This patch adds a driver for the Page-based Address Translator (PAT)
present on various TI SoCs. A PAT device performs address translation
using tables stored in an internal SRAM. Each PAT supports a set number
of pages, each occupying a programmable 4KB, 16KB, 64KB, or 1MB of
addresses in a window for which an incoming transaction will be
translated.

Signed-off-by: Andrew F. Davis <afd@ti.com>
[t-kristo@ti.com: added depends on ARCH_K3 to Kconfig]
Signed-off-by: Tero Kristo <t-kristo@ti.com>