U-Boot is a bit special piese of software because it is being
only executed once on power-on as compared to operating system
for example. That's why we don't care much about performance
optimizations instead we're more concerned about size. And up-to-date
compilers might produce much smaller code compared to
performance-optimized routines copy-pasted from the Linux kernel.

Here's an example:
------------------------------->8--------------------------
--- size_asm_strings.txt
+++ size_c_strings.txt
@@ -1,2 +1,2 @@
    text	   data	    bss	    dec	    hex	filename
- 121260	   3784	   3308	 128352	  1f560	u-boot
+ 120448	   3784	   3308	 127540	  1f234	u-boot
------------------------------->8--------------------------

See we were able to shave off ~800 bytes of .text section.

Also usage of string routines implemented in C gives us an ability
to support more HW flavors for free: generated instructions will match
our target as long as correct compiler option is used.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

These are header files used by ARC700 architecture.

Also note that "arch-arc700/hardware.h" is only required for compilation of
"designware_i2c" driver which refers to "asm/arch/hardware.h".
It would be good to fix mentioned driver sometime soon but it will cause
changes in ARM board configs that use "designware_i2c".

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Francois Bedard <fbedard@synopsys.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Heiko Schocher <hs@denx.de>