base: Ensure %p format arguments are printed as pointers.

base: Ensure %p format arguments are printed as pointers.

If the %p format is used, char * arguments should be printed as the
hex value of their pointer, not as strings. Unfortunately blindly
passing them to an ostream using << will not do that. This change adds
some casting in that case to ensure that they're treated as numbers and
not as strings.

Change-Id: If02bae6d5e468b352266702fcba62b6beddffcbd
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21459
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>