arm64: hyp-stub: Forbid kprobing of the hyp-stub

arm64: hyp-stub: Forbid kprobing of the hyp-stub

The hyp-stub is loaded by the kernel's early startup code at EL2
during boot, before KVM takes ownership later. The hyp-stub's
text is part of the regular kernel text, meaning it can be kprobed.

A breakpoint in the hyp-stub causes the CPU to spin in el2_sync_invalid.

Add it to the __hyp_text.

Signed-off-by: James Morse <james.morse@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will.deacon@arm.com>