libplatform: use SPDX short identifier for PHP license

Signed-off-by: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libplatform/libplatform.mk

@@ -6,7 +6,7 @@
 
 LIBPLATFORM_VERSION = feafe68e3e0b02c3261aefb3d711863ef6fadd38
 LIBPLATFORM_SITE = $(call github,Pulse-Eight,platform,$(LIBPLATFORM_VERSION))
-LIBPLATFORM_LICENSE = GPL-2.0+, PHP license v3.01
+LIBPLATFORM_LICENSE = GPL-2.0+, PHP-3.01
 LIBPLATFORM_LICENSE_FILES = src/os.h src/util/fstrcmp.c
 LIBPLATFORM_INSTALL_STAGING = YES