[aarch64] Change two function declaration types

[aarch64] Change two function declaration types

Commit r271514 missed changing the type of two functions in
aarch64-protos.h.  The function definitions had been updated to use
uint64_t while the function declarations had been missed.
They were missed since I only tested the patch on aarch64 where
`unsigned long` is the same as `uint64_t`.

This patch updates these declarations in aarch64-protos.h.

Tested by building an aarch64 cross-compiler on arm-none-linux-gnu (so
that `unsigned long` and `uint64_t` are different and would give error
messages), and bootstrapping on aarch64-none-linux-gnu.
Also manually tested command line options to see that
-march=armv8-a+typo prints out the expected flags while using the new
feature flags does not complain about missing flags.

gcc/ChangeLog:

2019-05-24  Matthew Malcomson  <matthew.malcomson@arm.com>

	PR target/90588
	* common/config/aarch64/aarch64-common.c
	(aarch64_rewrite_selected_cpu): Change local temporary variable
	type from unsigned long to uint64_t.
	* config/aarch64/aarch64-protos.h (aarch64_parse_extension,
	aarch64_get_extension_string_for_isa_flags): Change declaration to
	match new definition by replacing unsigned long with uint64_t.

From-SVN: r271599