tpm_tis: Allow tpm_tis to be bound using DT

This provides an open firwmare driver binding for tpm_tis. OF
is useful on arches where ACPI/PNP is not used.

The tcg,tpm-tis-mmio register map interface is specified by the TCG.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Documentation/devicetree/bindings/security/tpm/tpm_tis_mmio.txt

@@ -0,0 +1,25 @@
+Trusted Computing Group MMIO Trusted Platform Module
+
+The TCG defines multi vendor standard for accessing a TPM chip, this
+is the standard protocol defined to access the TPM via MMIO. Typically
+this interface will be implemented over Intel's LPC bus.
+
+Refer to the 'TCG PC Client Specific TPM Interface Specification (TIS)' TCG
+publication for the specification.
+
+Required properties:
+
+- compatible: should contain a string below for the chip, followed by
+              "tcg,tpm-tis-mmio". Valid chip strings are:
+	          * "atmel,at97sc3204"
+- reg: The location of the MMIO registers, should be at least 0x5000 bytes
+- interrupt-parent/interrupts: An optional interrupt indicating command completion.
+
+Example:
+
+	tpm_tis@90000 {
+				compatible = "atmel,at97sc3204", "tcg,tpm-tis-mmio";
+				reg = <0x90000 0x5000>;
+				interrupt-parent = <&EIC0>;
+				interrupts = <1 2>;
+	};