spi: fsl: Remove unused extern declarations

commit b36ece83 ("spi/mpc8xxx: refactor the common code for SPI/eSPI controller")
left mpc8xxx_spi_bufs() behind.
And since commit 3c5395b6 ("spi: fsl-(e)spi: simplify cleanup code")
mpc8xxx_spi_remove() is not used anymore.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20230725135411.21152-1-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-lib.h

@@ -103,12 +103,9 @@ extern void mpc8xxx_spi_rx_buf_u32(u32 data, struct mpc8xxx_spi *mpc8xxx_spi);
 
 extern struct mpc8xxx_spi_probe_info *to_of_pinfo(
 		struct fsl_spi_platform_data *pdata);
-extern int mpc8xxx_spi_bufs(struct mpc8xxx_spi *mspi,
-		struct spi_transfer *t, unsigned int len);
 extern const char *mpc8xxx_spi_strmode(unsigned int flags);
 extern void mpc8xxx_spi_probe(struct device *dev, struct resource *mem,
 		unsigned int irq);
-extern int mpc8xxx_spi_remove(struct device *dev);
 extern int of_mpc8xxx_spi_probe(struct platform_device *ofdev);
 
 #endif /* __SPI_FSL_LIB_H__ */