ppp: update deprecated cpe

ppp: update deprecated cpe

The CPE 'samba:ppp' added in OpenWrt commit [1], has been deprecated in
favour of 'point-to-point_protocol_project:point-to-point_protocol'
(see [2]).

[1] c61a239514 add PKG_CPE_ID ids to package and tools
[2] https://nvd.nist.gov/products/cpe/detail/1224B76D-6BB3-4088-9F42-23AC04A764F2

Signed-off-by: Thomas Perale <thomas.perale@mind.be>
Link: https://github.com/openwrt/openwrt/pull/21441
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit dd519f6c05b37e2a676cc20991d2525066fe6d06)