Blackfin arch: Remove redundant kernel option

use kernel command line mem and max_mem bootargs to limit
availabe memory instead.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index d0f7ff3..c602727 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -310,11 +310,6 @@
 	  are also not changed, and the Bootloader does 100% of the hardware
 	  configuration.
 
-config MEM_SIZE
-	int "SDRAM Memory Size in MBytes"
-	depends on BFIN_KERNEL_CLOCK
-	default 64
-
 config PLL_BYPASS
 	bool "Bypass PLL"
 	depends on BFIN_KERNEL_CLOCK
@@ -376,7 +371,7 @@
 
 config MAX_MEM_SIZE
 	int "Max SDRAM Memory Size in MBytes"
-	depends on !BFIN_KERNEL_CLOCK && !MPU
+	depends on !MPU
 	default 512
 	help
 	  This is the max memory size that the kernel will create CPLB