CPER Specification wrong link in cper-records document

[tpaz]

the CPER cpecification is mentioned twice (at least) in https://github.com/openbmc/docs/blob/master/designs/cper-records.md
yet the link actually points to Arm developer site where SBMR documentation can be found (https://developer.arm.com/documentation/den0069/latest/), not the CPER SPEC.
The correct link(s) should be to: https://uefi.org/specs/UEFI/2.10_A/Apx_N_Common_Platform_Error_Record.html

[edtanous]

@tpaz can you please send a Gerrit review to fix the bad link? There was quite a bit of shifting on that doc where some sections pointed to SBMR, some to UEFI, and clearly this one got messed up.