libjpeg: use SPDX short identifier

Use IJG instead of jpeg-license

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 1350678212495925e9800772a82ed6a5894d2da7)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libjpeg/libjpeg.mk

@@ -7,7 +7,7 @@
 LIBJPEG_VERSION = 9b
 LIBJPEG_SITE = http://www.ijg.org/files
 LIBJPEG_SOURCE = jpegsrc.v$(LIBJPEG_VERSION).tar.gz
-LIBJPEG_LICENSE = jpeg-license (BSD-3-Clause-like)
+LIBJPEG_LICENSE = IJG
 LIBJPEG_LICENSE_FILES = README
 LIBJPEG_INSTALL_STAGING = YES
 LIBJPEG_PROVIDES = jpeg