soc/intel/cmn/pch: Consolidate eSPI.h into IA common code

This patch moves the SoC-specific `eSPI.h` file into the IA common
code to promote code reuse and reduce duplication across different
SoC generations.

TEST=Builds successfully for google/rex.

Change-Id: Icb09421eec45c1ef8ab50252543b000078f18b21
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83483
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>

src/soc/intel/common/pch/include/intelpch/espi.h

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _INTELPCH_ESPI_H_
+#define _INTELPCH_ESPI_H_
+
+/* PCI Configuration Space (D31:F0): ESPI */
+#define SCI_IRQ_SEL		(7 << 0)
+#define SCIS_IRQ9		0
+#define SCIS_IRQ10		1
+#define SCIS_IRQ11		2
+#define SCIS_IRQ20		4
+#define SCIS_IRQ21		5
+#define SCIS_IRQ22		6
+#define SCIS_IRQ23		7
+#define SERIRQ_CNTL		0x64
+#define ESPI_IO_DEC		0x80 /* IO Decode Ranges Register */
+#define   COMA_RANGE		0x0 /* 0x3F8 - 0x3FF COM1 */
+#define   COMB_RANGE		0x1 /* 0x2F8 - 0x2FF COM2 */
+#define ESPI_GEN1_DEC		0x84 /* ESPI IF Generic Decode Range 1 */
+#define ESPI_GEN2_DEC		0x88 /* ESPI IF Generic Decode Range 2 */
+#define ESPI_GEN3_DEC		0x8c /* ESPI IF Generic Decode Range 3 */
+#define ESPI_GEN4_DEC		0x90 /* ESPI IF Generic Decode Range 4 */
+#define LGMR			0x98 /* ESPI Generic Memory Range */
+#define PCCTL			0xE0 /* PCI Clock Control */
+#define   CLKRUN_EN		(1 << 0)
+
+#endif /* _INTELPCH_ESPI_H_ */