soc/amd/picasso: split southbridge into bootblock and ramstage code

The ramstage parts gets renamed to fch.c and the bootblock one to
early_fch.c. No functionality from the old southbridge file is used in
romstage, so don't link it there.

Change-Id: I7ca3b5238c3b841191dd0459996b691edd76fbf8
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48439
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/picasso/Makefile.inc

@@ -13,7 +13,7 @@ all-y += config.c
 
 bootblock-y += bootblock.c
 bootblock-y += aoac.c
-bootblock-y += southbridge.c
+bootblock-y += early_fch.c
 bootblock-y += i2c.c
 bootblock-y += uart.c
 bootblock-$(CONFIG_PICASSO_CONSOLE_UART) += uart_console.c
@@ -28,7 +28,6 @@ romstage-y += memmap.c
 romstage-y += uart.c
 romstage-$(CONFIG_PICASSO_CONSOLE_UART) += uart_console.c
 romstage-y += aoac.c
-romstage-y += southbridge.c
 romstage-y += psp.c
 romstage-y += mrc_cache.c
 
@@ -49,7 +48,7 @@ ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += agesa_acpi.c
 ramstage-y += gpio.c
 ramstage-y += aoac.c
-ramstage-y += southbridge.c
+ramstage-y += fch.c
 ramstage-y += reset.c
 ramstage-y += acp.c
 ramstage-y += sata.c