EDAC/i5000: Fix snprintf() size calculation in calculate_dimm_size()

The snprintf() can't really overflow because we're writing a max of 42
bytes to a PAGE_SIZE buffer.  But the limit calculation doesn't take
the first 11 bytes that we wrote into consideration so the limit is
not correct.  Just fix it for correctness even though it doesn't
affect runtime.

Fixes: 64e1fda ("i5000_edac: Fix the logic that retrieves memory information")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://patch.msgid.link/07cd652c51e77aad5a8350e1a7cd9407e5bbe373.1765290801.git.dan.carpenter@linaro.org

Author: Dan Carpenter

drivers/edac/i5000_edac.c

@@ -1111,6 +1111,7 @@ static void calculate_dimm_size(struct i5000_pvt *pvt)
 
 	n = snprintf(p, space, "           ");
 	p += n;
+	space -= n;
 	for (branch = 0; branch < MAX_BRANCHES; branch++) {
 		n = snprintf(p, space, "       branch %d       | ", branch);
 		p += n;