“GPL”: Module is licensed under GPL version 2. This does not express any distinction between GPL-2.0-only or GPL-2.0-or-later. The exact license information can only be determined via the license information in the corresponding source files.
“GPL v2” Same as “GPL”. It exists for historic reasons.
This prevents the driver from being built as a module. https://github.com/msm8953-mainline/linux/blob/e1fa6540c38cd7f0111217c45b2111cdb1f40345/drivers/gpu/drm/panel/panel-ili7807-fhdplus.c#L270
From https://www.kernel.org/doc/html/latest/process/license-rules.html on MODULE_LICENSE usage: