src/(device/lib/soc): Remove unused variables

When building grunt with flags set to detect variables that get a value but
then are unused, there are 5 instances that causes error (unused variable).
In most cases it's enough to simply remove the variable. Other instances,
is better to simply use the variables (one instance it's a return value, on
the other instance using the variables makes code more readable).

BUG=b:120260448
TEST=Build and boot grunt.

Change-Id: I0d00fb6a42db20afb34c76b9445a741a57096ead
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/c/29985
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/stoneyridge/lpc.c b/src/soc/amd/stoneyridge/lpc.c
index 317574b..efc948d 100644
--- a/src/soc/amd/stoneyridge/lpc.c
+++ b/src/soc/amd/stoneyridge/lpc.c
@@ -145,6 +145,7 @@
 
 	/* Allocate ACPI NVS in CBMEM */
 	gnvs = cbmem_add(CBMEM_ID_ACPI_GNVS, sizeof(global_nvs_t));
+	printk(BIOS_DEBUG, "ACPI GNVS at %p\n", gnvs);
 }
 
 static void lpc_set_resources(struct device *dev)