dt-bindings: mtd: ti,elm: Add support for AM64 ELM

TI's AM64 SoC has the Error Locator Module. Add compatible and
related properties to support ELM on AM64 SoC.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220326080726.30372-3-rogerq@kernel.org