Blackfin arch: fix typo in register name

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index cc789b9..c35f549 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -829,7 +829,7 @@
 
 comment "Asynchonous Memory Configuration"
 
-menu "EBIU_AMBCTL Global Control"
+menu "EBIU_AMGCTL Global Control"
 config C_AMCKEN
 	bool "Enable CLKOUT"
 	default y