ACPI S3: Remove HIGH_MEMORY_SAVE where possible

Add implementation to use actual requirements of ramstage size
for S3 resume backup in CBMEM. The backup covers complete pages of 4 KiB.

Only the required amount of low memory is backed up when ACPI_TINY_LOWMEM_BACKUP
is selected for the platform. Enable this option for AGESA and binaryPI, other
platforms (without RELOCATABLE_RAMSTAGE) currently keep their romstage ramstack
in low memory for s3 resume path.

Change-Id: Ide7ce013f3727c2928cdb00fbcc7e7e84e859ff1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15255
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>

src/Kconfig

@@ -539,6 +539,19 @@ config HAVE_ACPI_RESUME
 	bool
 	default n
 
+config ACPI_TINY_LOWMEM_BACKUP
+	bool
+	default n
+	help
+	  On S3 resume path, backup only the region of low memory ramstage
+	  will occupy. Requires platform places romstage ramstack in CBMEM.
+
+config ACPI_HUGE_LOWMEM_BACKUP
+	bool
+	default !ACPI_TINY_LOWMEM_BACKUP
+	help
+	  On S3 resume path, backup low memory from RAMBASE..RAMTOP in CBMEM.
+
 config RESUME_PATH_SAME_AS_BOOT
 	bool
 	default y if ARCH_X86