MAINTAINERS: update X86 PLATFORM DRIVERS entry with new kernel.org git repo

The pdx86 maintainers have moved their git tree from infradead.org to
kernel.org, update the X86 PLATFORM DRIVERS MAINTAINERS entry for this.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

MAINTAINERS

@@ -18861,7 +18861,7 @@ M:	Hans de Goede <hdegoede@redhat.com>
 M:	Mark Gross <mgross@linux.intel.com>
 L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
-T:	git git://git.infradead.org/linux-platform-drivers-x86.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git
 F:	drivers/platform/olpc/
 F:	drivers/platform/x86/