soc/amd/stoneyridge: Call sb_acpi_mmio_decode()

Call function sb_acpi_mmio_decode() from bootblock_fch_early_init().
This enables decoding of the FCH ACPI MMIO regions 0xfed80000 -
0xfed81fff.  This is another step to moving AGESA out of the bootblock
for StoneyRidge

BUG=b:74586747
BRANCH=master
TEST=Build and boot on Grunt.

Change-Id: I8cf329e5cd2002b225742fefa5c1ddd2598de674
Signed-off-by: Garrett Kirkendall <garrett.kirkendall@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/25161
Reviewed-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/stoneyridge/southbridge.c

@@ -559,6 +559,7 @@ void bootblock_fch_early_init(void)
 	sb_enable_rom();
 	sb_lpc_port80();
 	sb_lpc_decode();
+	sb_acpi_mmio_decode();
 }
 
 void sb_enable(device_t dev)