libpaylod: fix lpgcc logic statement

The -z "${V}" sure must have meant to be -n "${V}", but come to think
of it, this check is not necessary, as the following check will
succeed if and only if V is set to 1.

BUG=none
TEST=verified that adding V=1 to the environment causes the lpgcc
     debug statements to show up in the output.

Original-Change-Id: I1eb43ef49aeb4f16aef4fbee3a1037e853f9b40f
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/200501
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-by: Marc Jones <marc.jones@se-eng.com>
(cherry picked from commit 7d69a292b1dc90e68e539e329f019098f8af5007)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I63785fd9fc88b95d50ecced1f4f74a76ca68089c
Reviewed-on: http://review.coreboot.org/7912
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)

payloads/libpayload/bin/lpgcc

@@ -27,7 +27,7 @@
 ## SUCH DAMAGE.
 
 # GCC wrapper for libpayload
-if [ -z "${V}" ] && [ "${V}" = 1 ]; then
+if [ "${V}" = "1" ]; then
 	DEBUGME=1
 else
 	DEBUGME=0