avr32/config.mk: simplify PLATFORM_RELFLAGS

This patch removes PLATFORM_RELFLAGS from board specific config.mk files and
define them in arch specific config.mk file.

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
diff --git a/arch/avr32/config.mk b/arch/avr32/config.mk
index ef14710..a751a3d 100644
--- a/arch/avr32/config.mk
+++ b/arch/avr32/config.mk
@@ -26,4 +26,6 @@
 CONFIG_STANDALONE_LOAD_ADDR ?= 0x00000000
 
 PLATFORM_RELFLAGS	+= -ffixed-r5 -fPIC -mno-init-got -mrelax
+PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
+
 LDFLAGS_u-boot		= --gc-sections --relax
diff --git a/board/atmel/atngw100/config.mk b/board/atmel/atngw100/config.mk
index c3c7433..34b709a 100644
--- a/board/atmel/atngw100/config.mk
+++ b/board/atmel/atngw100/config.mk
@@ -1,2 +1 @@
 CONFIG_SYS_TEXT_BASE		= 0x00000000
-PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
diff --git a/board/atmel/atstk1000/config.mk b/board/atmel/atstk1000/config.mk
index 455b0d5..34b709a 100644
--- a/board/atmel/atstk1000/config.mk
+++ b/board/atmel/atstk1000/config.mk
@@ -1,2 +1 @@
-PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
 CONFIG_SYS_TEXT_BASE		= 0x00000000
diff --git a/board/earthlcd/favr-32-ezkit/config.mk b/board/earthlcd/favr-32-ezkit/config.mk
index 455b0d5..34b709a 100644
--- a/board/earthlcd/favr-32-ezkit/config.mk
+++ b/board/earthlcd/favr-32-ezkit/config.mk
@@ -1,2 +1 @@
-PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
 CONFIG_SYS_TEXT_BASE		= 0x00000000
diff --git a/board/mimc/mimc200/config.mk b/board/mimc/mimc200/config.mk
index c3c7433..34b709a 100644
--- a/board/mimc/mimc200/config.mk
+++ b/board/mimc/mimc200/config.mk
@@ -1,2 +1 @@
 CONFIG_SYS_TEXT_BASE		= 0x00000000
-PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
diff --git a/board/miromico/hammerhead/config.mk b/board/miromico/hammerhead/config.mk
index c3c7433..34b709a 100644
--- a/board/miromico/hammerhead/config.mk
+++ b/board/miromico/hammerhead/config.mk
@@ -1,2 +1 @@
 CONFIG_SYS_TEXT_BASE		= 0x00000000
-PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections