can: mcp251xfd: mcp251xfd_reg_invalid(): rename from mcp251xfd_osc_invalid()

This patch renames mcp251xfd_osc_invalid() to mcp251xfd_reg_invalid(),
as it will be used for other registers than the "osc" register in a
later patch.

This patch also moves this function to more towards the beginning of
the file, to be available for other functions, too.

Link: https://lore.kernel.org/all/20220207131047.282110-2-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

@@ -178,6 +178,11 @@ static int mcp251xfd_clks_and_vdd_disable(const struct mcp251xfd_priv *priv)
 	return 0;
 }
 
+static inline bool mcp251xfd_reg_invalid(u32 reg)
+{
+	return reg == 0x0 || reg == 0xffffffff;
+}
+
 static inline int
 mcp251xfd_chip_get_mode(const struct mcp251xfd_priv *priv, u8 *mode)
 {
@@ -241,11 +246,6 @@ mcp251xfd_chip_set_mode_nowait(const struct mcp251xfd_priv *priv,
 	return __mcp251xfd_chip_set_mode(priv, mode_req, true);
 }
 
-static inline bool mcp251xfd_osc_invalid(u32 reg)
-{
-	return reg == 0x0 || reg == 0xffffffff;
-}
-
 static int mcp251xfd_chip_clock_enable(const struct mcp251xfd_priv *priv)
 {
 	u32 osc, osc_reference, osc_mask;
@@ -274,7 +274,7 @@ static int mcp251xfd_chip_clock_enable(const struct mcp251xfd_priv *priv)
 				       (osc & osc_mask) == osc_reference,
 				       MCP251XFD_OSC_STAB_SLEEP_US,
 				       MCP251XFD_OSC_STAB_TIMEOUT_US);
-	if (mcp251xfd_osc_invalid(osc)) {
+	if (mcp251xfd_reg_invalid(osc)) {
 		netdev_err(priv->ndev,
 			   "Failed to detect %s (osc=0x%08x).\n",
 			   mcp251xfd_get_model_str(priv), osc);