espi: it8xxx2: make sure h2ram offset is configured correctly

This change for addressing the below symptoms.
Two FW images have different h2ram offset settings.
Jumping to each other will cause offset setting errors.

Signed-off-by: Dino Li <Dino.Li@ite.com.tw>

drivers/espi/espi_it8xxx2.c

@@ -196,6 +196,7 @@ static const struct ec2i_t pmc2_settings[] = {
  * Linker script of h2ram.ld will make the pool 4K aligned.
  */
 #define IT8XXX2_ESPI_H2RAM_POOL_SIZE_MAX 0x1000
+#define IT8XXX2_ESPI_H2RAM_OFFSET_MASK   GENMASK(3, 0)
 
 #if defined(CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION)
 #define H2RAM_ACPI_SHM_MAX ((CONFIG_ESPI_IT8XXX2_ACPI_SHM_H2RAM_SIZE) + \
@@ -249,7 +250,9 @@ static void smfi_it8xxx2_init(const struct device *dev)
 	/* Set the host to RAM cycle address offset */
 	h2ram_offset = ((uint32_t)h2ram_pool & 0xffff) /
 				IT8XXX2_ESPI_H2RAM_POOL_SIZE_MAX;
-	gctrl->GCTRL_H2ROFSR |= h2ram_offset;
+	gctrl->GCTRL_H2ROFSR =
+		(gctrl->GCTRL_H2ROFSR & ~IT8XXX2_ESPI_H2RAM_OFFSET_MASK) |
+		h2ram_offset;
 
 #ifdef CONFIG_ESPI_PERIPHERAL_EC_HOST_CMD
 	memset(&h2ram_pool[CONFIG_ESPI_PERIPHERAL_HOST_CMD_PARAM_PORT_NUM], 0,