xtensa: disable link optimization

The default linker behavior is to optimize identical literal values
and remove unnecessary overhead. However, because of a bug in the
linker, this currently results in an error ('call target out of range').

Disable link-time optimizations per default until there is a fix
for the linker and add the option to iss_defconfig.
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/Kconfig.debug

@@ -14,7 +14,7 @@ config DEBUG_TLB_SANITY
 
 config LD_NO_RELAX
 	bool "Disable linker relaxation"
-	default n
+	default y
 	help
 	  Enable this function to disable link-time optimizations.
 	  The default linker behavior is to combine identical literal

arch/xtensa/configs/iss_defconfig

@@ -757,3 +757,4 @@ CONFIG_GENERIC_FIND_LAST_BIT=y
 CONFIG_HAS_IOMEM=y
 CONFIG_HAS_DMA=y
 CONFIG_NLATTR=y
+CONFIG_LD_NO_RELAX=y