csky: change a Kconfig symbol name to fix e1000 build error

e1000's #define of CONFIG_RAM_BASE conflicts with a Kconfig symbol in
arch/csky/Kconfig.

The symbol in e1000 has been around longer, so change arch/csky/ to use
DRAM_BASE instead of RAM_BASE to remove the conflict.  (although e1000
is also a 2-line change)

Link: https://lkml.kernel.org/r/20210411055335.7111-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/csky/Kconfig

@@ -314,7 +314,7 @@ config FORCE_MAX_ZONEORDER
  int "Maximum zone order"
  default "11"
 
-config RAM_BASE
+config DRAM_BASE
  hex "DRAM start addr (the same with memory-section in dts)"
  default 0x0
 

arch/csky/include/asm/page.h

@@ -28,7 +28,7 @@
 #define SSEG_SIZE 0x20000000
 #define LOWMEM_LIMIT (SSEG_SIZE * 2)
 
-#define PHYS_OFFSET_OFFSET (CONFIG_RAM_BASE & (SSEG_SIZE - 1))
+#define PHYS_OFFSET_OFFSET (CONFIG_DRAM_BASE & (SSEG_SIZE - 1))
 
 #ifndef __ASSEMBLY__