options: fix cl_target_option_print_diff() with strings

options: fix cl_target_option_print_diff() with strings

Fix an obvious copy-and-paste error where ptr1 was used instead of ptr2.
This bug caused the dump file produced by -fdump-ipa-inline-details to
not correctly show the difference in target options when a function
could not be inlined due to a target option mismatch.

gcc/ChangeLog:
	PR bootstrap/90543
	* optc-save-gen.awk: Fix copy-and-paste error.

Signed-off-by: Eric Biggers <ebiggers@google.com>