tegra132: never recover cbmem from romstage

Tegra132 has 2 different paths for booting and resuming from
sleep. The boot path uses the typical bootblock, romstage,
and ramstage. However, the resume path is completely orthogonal.
cbmem_initialize() attempts to recover the cbmem area, but
that functionality should not be used from romstage because
tegra132 is by definition in a fresh boot if it is executing
romstage. Therefore, use cbmem_initialize_empty() so that cbmem
is always initialized from scratch on each boot.

BUG=chrome-os-partner:31239
BRANCH=None
TEST=Built and ran on ryu. Was able to enter recovery and stay in
     recovery without entering a reboot loop.

Change-Id: I0453c15e57a873a7ce7a63190dceafb75e4c9342
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 28ebc092e6721552c18db03e7578424c23a64b64
Original-Change-Id: I2016146fdc3aea493a78bab31ea8c8cbd78935c5
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/211424
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8990
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/soc/nvidia/tegra132/romstage.c

@@ -77,7 +77,12 @@ void romstage(void)
 	 */
 	trustzone_region_init();
 
-	cbmem_initialize();
+	/*
+	 * When romstage is running it's always on the reboot path -- never a
+	 * resume path where cbmem recovery is required. Therefore, always
+	 * initialize the cbmem area to be empty.
+	 */
+	cbmem_initialize_empty();
 
 	ccplex_cpu_prepare();
 	printk(BIOS_INFO, "T132 romstage: cpu prepare done\n");