board_f: powerpc: Use timer_init() instead of init_timebase()

There is no good reason to use a different name on PowerPC. Change it to
timer_init() like the others.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: York Sun <york.sun@nxp.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/freescale/mpc8313erdb/mpc8313erdb.c b/board/freescale/mpc8313erdb/mpc8313erdb.c
index eac193e..693dff6 100644
--- a/board/freescale/mpc8313erdb/mpc8313erdb.c
+++ b/board/freescale/mpc8313erdb/mpc8313erdb.c
@@ -133,7 +133,7 @@
 	NS16550_init((NS16550_t)(CONFIG_SYS_IMMR + 0x4500),
 		     CONFIG_SYS_NS16550_CLK / 16 / CONFIG_BAUDRATE);
 	puts("NAND boot... ");
-	init_timebase();
+	timer_init();
 	initdram(0);
 	relocate_code(CONFIG_SYS_NAND_U_BOOT_RELOC_SP, (gd_t *)gd,
 		      CONFIG_SYS_NAND_U_BOOT_RELOC);