dev-hsa: Add missing include to hsa_driver.hh

dev-hsa: Add missing include to hsa_driver.hh

Due to using ThreadContext::Suspended in hsa_driver.hh as of
965ad12b9a4ae4035b0f63e7ab083ac87258a071, we now need to include
cpu/thread_context.hh. This change fixes that.

Change-Id: I2c6882f2a29ca1638dd34cda42874b95cafbe548
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40216
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>