Revert "break build if it would produce broken binary"

The root cause of this problem should now be fixed.

This reverts commit a6a4c542d3.
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Pavel Machek <pavel@denx.de>
Tested-by: Pavel Machek <pavel@denx.de>

arch/arm/include/asm/u-boot.h

@@ -49,8 +49,4 @@ typedef struct bd_info {
 #define IH_ARCH_DEFAULT IH_ARCH_ARM64
 #endif
 
-#if defined(CONFIG_USE_PRIVATE_LIBGCC) && defined(CONFIG_SYS_THUMB_BUILD)
-#error Thumb build does not work with private libgcc.
-#endif
-
 #endif	/* _U_BOOT_H_ */