sha: implement SHA engine calls

[DacoTaco]

while looking through the reverse engineering of the SHA engine for starstruck i noticed it was actually super easy to use, and applications like priiloader could use it to validate content integrity.
this would mean all software based sha implementations can be replaced with the hardware implementation on the wii.

this has been tested with the following code :

//input should always be 64bit aligned, in the actual code this was not on the stack but rather a global
u8 input[0x0400000] [[gnu::aligned(64)]];

//actual test
gprintf("starting context\n");
sha_context context [[gnu::aligned(32)]];
u32 output[5] [[gnu::aligned(32)]];
memset(output, 0, sizeof(output));
ret = SHA_InitializeContext(&context);
if(ret < 0)
{
	gprintf("failed to reset SHA : %d.\n", ret);
	return 0;
}

memcpy(input, input_bin, input_bin_size);
gprintf("copied %d bytes of data\n", input_bin_size);

ret = SHA_Calculate(&context, input, input_bin_size, output);
if(ret < 0)
{
	gprintf("failed to calc SHA : %d.\n", ret);
	return 0;
}

gprintf("final hash : %08X %08X %08X %08X %08X %08X\n", output[0], output[1], output[2], output[3], output[4]);
gprintf("test successful!\n");