soc/amd/stoneyridge/southbridge: replace southbridge prefix with fch

This aligns the function names with Picasso and Cezanne. Also move the
fch_* functions in the header file in the order they get called.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I49db8021edae5e537f043bf52eea1be54dc46eca
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50124
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/stoneyridge/southbridge.c

@@ -402,7 +402,7 @@ static void sb_init_acpi_ports(void)
 				PM_ACPI_TIMER_EN_EN);
 }
 
-void southbridge_init(void *chip_info)
+void fch_init(void *chip_info)
 {
 	struct chipset_power_state *state;
 
@@ -461,7 +461,7 @@ static void set_sb_gnvs(struct global_nvs *gnvs)
 			& ~PCI_BASE_ADDRESS_MEM_ATTR_MASK;
 }
 
-void southbridge_final(void *chip_info)
+void fch_final(void *chip_info)
 {
 	uint8_t restored_power = PM_S5_AT_POWER_RECOVERY;