FRV: Make NOMMU-mode work with base addresses other than 0xC0000000 [try #2]

Make NOMMU-mode work with base addresses other than 0xC0000000 by:

 (1) Giving the code that sets up the protection registers the right address
     in __sdram_base.  Rather than being hard coded to 0xC0000000, the value
     of __page_offset is obtained from the linker script.

 (2) Eliminate the check in __switch_to() that verifies the current thread
     info is in the 0xCxxxxxxx region.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/frv/kernel/head.inc b/arch/frv/kernel/head.inc
index d424cd2..bff6662 100644
--- a/arch/frv/kernel/head.inc
+++ b/arch/frv/kernel/head.inc
@@ -46,5 +46,5 @@
 #ifdef CONFIG_MMU
 __sdram_base = 0x00000000		/* base address to which SDRAM relocated */
 #else
-__sdram_base = 0xc0000000		/* base address to which SDRAM relocated */
+__sdram_base = __page_offset		/* base address to which SDRAM relocated */
 #endif