[S] Change in coreboot[main]: [MTL-x64]src/intel/common: Add support for 32bit memcpy.

[Subrata Banik (Code Review)]

Attention is currently required from: Jérémy Compostella, Saurabh Mishra.

Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81927?usp=email )

Change subject: [MTL-x64]src/intel/common: Add support for 32bit memcpy.
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Patch Set 4:

(2 comments)

File src/arch/x86/memcpy.c:

https://review.coreboot.org/c/coreboot/+/81927/comment/f9b66aca_cb25d175 :
PS4, Line 19: 		"rep ; movsq\n\t"
            : 		"mov %4,%%rcx\n\t"
            : 		"rep ; movsb\n\t"
            : 		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
            : 		: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
            : 		: "memory"
            : 	);
why don't you leverage this section to implement 64-bit memcopy ? rather implementing a new func?

https://review.coreboot.org/c/coreboot/+/81927/comment/6ddef761_fdec8323 :
PS4, Line 41: #if ENV_X86_64
why guard this function?

```
void *memcpy32(void* dest, const void* src, size_t n)
{
    if (!ENV_X86_64)
       return NULL;

....
}
```