cupsfilters: ieee1284: fix out-of-bounds read in NormalizeMakeModel

[nomkar24]

When a user-supplied make string is longer than bufsize, snprintf() truncates the output but modelptr was still calculated using the original strlen(make), resulting in modelptr pointing past the end of buffer. A subsequent strncasecmp() call then caused an out-of-bounds read.

Key changes:

• Add bounds check for modelptr after all snprintf() calls that set it to a fixed offset (Xerox, Kodak, Apple, Seiko, EFI, Canon, Fargo, HP, Kyocera, and user-supplied make string cases)
• Add strlen(buffer) guard before accessing buffer at fixed indices in the known multi-word manufacturer name checks (konica minolta, fuji xerox, lexmark international, kyocera mita)
• Add strlen(make) < bufsize guard before accessing buffer[strlen(make)] to prevent out-of-bounds access in the make-prefix match check
• Keep a catch-all safety clamp for modelptr at the end of the manufacturer block
• #Fixes stack-buffer-overflow in cfIEEE1284NormalizeMakeModel() #136