nvramcui: fix a buffer overflow

Missing parentheses around addition.

==22611== Invalid write of size 8
==22611==    at 0x401B26: main (nvramcui.c:146)
==22611==  Address 0x5a67c40 is 32 bytes inside a block of size 33 alloc'd
==22611==    at 0x4C2BC0F: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==22611==    by 0x401AA9: main (nvramcui.c:137)

Change-Id: I9fd6a619dd03ebaaa066bca8fa5838e76374c984
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-on: http://review.coreboot.org/8527
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

payloads/nvramcui/nvramcui.c

@@ -149,7 +149,7 @@ int main()
 				cmos_enum = next_cmos_enum_of_id(cmos_enum, option->config_id);
 			}
 
-			char **values = malloc(sizeof(char*)*numvals + 1);
+			char **values = malloc(sizeof(char*)*(numvals + 1));
 			int cnt = 0;
 
 			cmos_enum = first_cmos_enum_of_id(opttbl, option->config_id);