powerpc/rtas: Remove unused rtas_service_present()

rtas_service_present() has no more users.

rtas_function_implemented() is now the appropriate API for determining
whether a given RTAS function is available to call.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231106-rtas-trivial-v1-4-61847655c51f@linux.ibm.com

arch/powerpc/include/asm/rtas.h

@@ -409,7 +409,6 @@ static inline bool rtas_function_implemented(const rtas_fn_handle_t handle)
 	return rtas_function_token(handle) != RTAS_UNKNOWN_SERVICE;
 }
 extern int rtas_token(const char *service);
-extern int rtas_service_present(const char *service);
 extern int rtas_call(int token, int, int, int *, ...);
 void rtas_call_unlocked(struct rtas_args *args, int token, int nargs,
 			int nret, ...);

arch/powerpc/kernel/rtas.c

@@ -900,11 +900,6 @@ int rtas_token(const char *service)
 }
 EXPORT_SYMBOL_GPL(rtas_token);
 
-int rtas_service_present(const char *service)
-{
-	return rtas_token(service) != RTAS_UNKNOWN_SERVICE;
-}
-
 #ifdef CONFIG_RTAS_ERROR_LOGGING
 
 static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;