lib/cbfs: Add CBFS_CACHE_ALIGN Kconfig option

This option will allow platforms to set the alignment of the cbfs_cache
buffers.

BUG=b:179699789
TEST=gdb -ex 'p cbfs_cache' /tmp/coreboot/guybrush/cbfs/fallback/ramstage.debug
$1 = {buf = 0x0, size = 0, alignment = 8, last_alloc = 0x0, second_to_last_alloc = 0x0, free_offset = 0}

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I74598d4bcbca9a01cc8c65012d7e4ae341d052b1
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58706
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/lib/Kconfig

@@ -99,6 +99,12 @@ config NO_CBFS_MCACHE
 	  lookup must re-read the same CBFS directory entries from flash to find
 	  the respective file.
 
+config CBFS_CACHE_ALIGN
+	int
+	default 8
+	help
+	  Sets the alignment of the buffers returned by the cbfs_cache.
+
 config PAYLOAD_PRELOAD
 	bool
 	depends on COOP_MULTITASKING