ARM: fix LTO build for some thumb-interwork cases

Fix LTO build for some thumb-interwork usecases (such as for
da850evm_defconfig), where inline assmebly such as
  mrc p15,0,r2,c1,c0,0
causes the compiler to fail during LTO linking with
  Error: selected processor does not support `mrc p15,0,r2,c1,c0,0'
         in Thumb mode

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/cpu/arm926ejs/Makefile

@@ -25,6 +25,8 @@ ifndef CONFIG_HAS_THUMB2
 
 CFLAGS_cpu.o := -marm
 CFLAGS_cache.o := -marm
+CFLAGS_REMOVE_cpu.o := $(LTO_CFLAGS)
+CFLAGS_REMOVE_cache.o := $(LTO_CFLAGS)
 
 endif
 endif

arch/arm/lib/Makefile

@@ -64,6 +64,7 @@ endif
 
 obj-y	+= cache.o
 obj-$(CONFIG_SYS_ARM_CACHE_CP15)	+= cache-cp15.o
+CFLAGS_REMOVE_cache-cp15.o := $(LTO_CFLAGS)
 
 obj-y	+= psci-dt.o