net: fs_enet: Remove fs_get_id()

fs_get_id() hasn't been used since commit b219108c ("fs_enet:
Remove !CONFIG_PPC_CPM_NEW_BINDING code")

Remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/7a53b88cc40302fcbea59554f5e7067e3594ad53.1691155346.git.christophe.leroy@csgroup.euSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/fs_enet_pd.h

@@ -151,15 +151,4 @@ struct fs_mii_fec_platform_info {
 	u32 mii_speed;
 };
 
-static inline int fs_get_id(struct fs_platform_info *fpi)
-{
-	if(strstr(fpi->fs_type, "SCC"))
-		return fs_scc_index2id(fpi->fs_no);
-	if(strstr(fpi->fs_type, "FCC"))
-		return fs_fcc_index2id(fpi->fs_no);
-	if(strstr(fpi->fs_type, "FEC"))
-		return fs_fec_index2id(fpi->fs_no);
-	return fpi->fs_no;
-}
-
 #endif