efivar: force shared libgcc for Nios II

efivar for Nios II also has to be linked with shared libgcc to avoid an
error due to FDE encoding in static libgcc when linking libefiboot.so.

Fixes:
http://autobuild.buildroot.net/results/0c9/0c90e3e7ad41d21dd832f6f266af35fc19185170/

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/efivar/efivar.mk

@@ -21,9 +21,9 @@ EFIVAR_MAKE_OPTS = \
 	BINTARGETS=efivar \
 	LDFLAGS="$(TARGET_LDFLAGS) -fPIC"
 
-# Explicitly linking with shared libgcc is required on MicroBlaze,
-# otherwise it fails due to FDE encoding in static libgcc.
-ifeq ($(BR2_microblaze),y)
+# Explicitly linking with shared libgcc is required on MicroBlaze and
+# Nios II, otherwise it fails due to FDE encoding in static libgcc.
+ifeq ($(BR2_microblaze)$(BR2_nios2),y)
 EFIVAR_MAKE_OPTS += SOFLAGS="-shared -shared-libgcc"
 endif