[sw,otbn] Fix otbn patch offset

The older OTBN boot binary in the `Earlgrey-PROD-A2-M6-ROM-RC1` ROM release is different from the one when PR #27679 was authored.

The instruction to be patched in the binary built on `Earlgrey-PROD-A2-M6-ROM-RC1` tag is 0x888:
```
xxd /tmp/boot.bin | grep '7b38 fac1'
00000880: 7bb9 0fc1 7b3a f841 7b38 fac1 0b77 2000  {...{:.A{8...w .
```

Change-Id: I6f69b55c81c15543d0879701f489f2748bbb7a0b
Signed-off-by: Yi-Hsuan Deng <[email protected]>

Author: sasdf

sw/device/silicon_creator/lib/drivers/otbn.c

@@ -268,7 +268,7 @@ rom_error_t sc_otbn_load_app(const sc_otbn_app_t app) {
 void sc_otbn_patch(void) {
   enum {
     // Offset in the code of the bad instruction:
-    kBugOffset = 0x958,
+    kBugOffset = 0x888,
     // The bad instruction is:
     // bn.rshi   w16, w20, w31 >> 192
     kBadInstr = 0xc1fa387b,