usb: fsl-mph-dr-of: mark fsl_usb2_mpc5121_init() static

This function is only called locally and should always have been static:

drivers/usb/host/fsl-mph-dr-of.c:291:5: error: no previous prototype for 'fsl_usb2_mpc5121_init' [-Werror=missing-prototypes]

Link: https://lkml.kernel.org/r/20231123110506.707903-6-arnd@kernel.org
Fixes: 230f7ede ("USB: add USB EHCI support for MPC5121 SoC")
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tudor Ambarus <tudor.ambarus@linaro.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/usb/host/fsl-mph-dr-of.c

@@ -288,7 +288,7 @@ static void fsl_usb2_mph_dr_of_remove(struct platform_device *ofdev)
 #define PHYCTRL_LSFE		(1 << 1)	/* Line State Filter Enable */
 #define PHYCTRL_PXE		(1 << 0)	/* PHY oscillator enable */
 
-int fsl_usb2_mpc5121_init(struct platform_device *pdev)
+static int fsl_usb2_mpc5121_init(struct platform_device *pdev)
 {
 	struct fsl_usb2_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct clk *clk;