hw/scsi/lsi53c895a: Use deposit32 rather than handcoded shift/mask

Use deposit32() rather than handcoded shifts/masks to update the
scratch registers. This is cleaner and incidentally avoids a clang
sanitizer complaint ("runtime error: left shift of 255 by 24 places
cannot be represented in type 'int'").
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi/lsi53c895a.c

@@ -1870,8 +1870,7 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
             int shift;
             n = (offset - 0x58) >> 2;
             shift = (offset & 3) * 8;
-            s->scratch[n] &= ~(0xff << shift);
-            s->scratch[n] |= (val & 0xff) << shift;
+            s->scratch[n] = deposit32(s->scratch[n], shift, 8, val);
         } else {
             BADF("Unhandled writeb 0x%x = 0x%x\n", offset, val);
         }