[PATCH] powerpc/8xx: export 'cpm_setbrg' for modules

Fix missing export for a loadable module build:

ERROR: modpost: "cpm_setbrg" [drivers/tty/serial/cpm_uart/cpm_uart.ko] undefined!

Fixes: 4128a89ac80d ("powerpc/8xx: move CPM1 related files from sysdev/ to platforms/8xx")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <redacted>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: clang-built-linux@googlegroups.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christophe Leroy <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/platforms/8xx/cpm1.c |    1 +
 1 file changed, 1 insertion(+)

--- linux-next-20210121.orig/arch/powerpc/platforms/8xx/cpm1.c
+++ linux-next-20210121/arch/powerpc/platforms/8xx/cpm1.c

@@ -280,6 +280,7 @@ cpm_setbrg(uint brg, uint rate)
 		out_be32(bp, (((BRG_UART_CLK_DIV16 / rate) - 1) << 1) |
 			      CPM_BRG_EN | CPM_BRG_DIV16);
 }
+EXPORT_SYMBOL(cpm_setbrg);
 
 struct cpm_ioport16 {
 	__be16 dir, par, odr_sor, dat, intr;