ARM: remove SPEAR entry in makefile

As the lastest spear directories are removed, delete the associated entry
in Makefile.

Fixes: 570c3dcfc153 ("arm: Remove spear600 boards and the rest of SPEAr support")
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/arch/arm/cpu/arm926ejs/Makefile b/arch/arm/cpu/arm926ejs/Makefile
index 7e7ad4f..8cfe3f0 100644
--- a/arch/arm/cpu/arm926ejs/Makefile
+++ b/arch/arm/cpu/arm926ejs/Makefile
@@ -13,7 +13,6 @@
 endif
 
 obj-$(if $(filter mxs,$(SOC)),y) += mxs/
-obj-$(if $(filter spear,$(SOC)),y) += spear/
 obj-$(CONFIG_ARCH_SUNXI) += sunxi/
 
 # some files can only build in ARM or THUMB2, not THUMB1