caif: Remove unused cfsrvl_getphyid

cfsrvl_getphyid() has been unused since 2011's commit
f3621440 ("caif: Use RCU and lists in cfcnfg.c for managing caif link layers")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241007004456.149899-1-linux@treblig.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>