[boot_rom] use generated header for spi device address

Signed-off-by: Timothy Chen <timothytim@google.com>
diff --git a/sw/device/boot_rom/bootstrap.c b/sw/device/boot_rom/bootstrap.c
index 10410ab..9eee13b 100644
--- a/sw/device/boot_rom/bootstrap.c
+++ b/sw/device/boot_rom/bootstrap.c
@@ -156,7 +156,8 @@
   dif_spi_device_t spi;
   CHECK(dif_spi_device_init(
             (dif_spi_device_params_t){
-                .base_addr = mmio_region_from_addr(0x40020000),
+                .base_addr =
+                    mmio_region_from_addr(TOP_EARLGREY_SPI_DEVICE_BASE_ADDR),
             },
             &spi) == kDifSpiDeviceOk,
         "Failed to initialize SPI.");