No need to expose BTM_ChangeEScoLinkParms

Only used in btm_sco.cc.

No need to check BTM_MAX_SCO_LINKS here.  The next check does that
already.

Bug: 195344796
Tag: #refactor
Test: cert/run
Change-Id: I475b02486bac9345a4df7d503f143d77b66bd073