mfd: ab8500: Fix ab8500-clk typo

Commit f4d41ad8 ("mfd: ab8500: Example using new OF_MFD_CELL MACRO")
has a typo error renaming "ab8500-clk" to "abx500-clk"
with the result att ALSA SoC audio broke as the clock
driver was not probing anymore. Fixed it up.

Fixes: f4d41ad8 ("mfd: ab8500: Example using new OF_MFD_CELL MACRO")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/ab8500-core.c

@@ -631,8 +631,8 @@ static const struct mfd_cell ab8500_devs[] = {
 		    NULL, NULL, 0, 0, "stericsson,ab8500-ext-regulator"),
 	OF_MFD_CELL("ab8500-regulator",
 		    NULL, NULL, 0, 0, "stericsson,ab8500-regulator"),
-	OF_MFD_CELL("abx500-clk",
-		    NULL, NULL, 0, 0, "stericsson,abx500-clk"),
+	OF_MFD_CELL("ab8500-clk",
+		    NULL, NULL, 0, 0, "stericsson,ab8500-clk"),
 	OF_MFD_CELL("ab8500-gpadc",
 		    NULL, NULL, 0, 0, "stericsson,ab8500-gpadc"),
 	OF_MFD_CELL("ab8500-rtc",