Public `generic_timer` for `armv7a`.

[luodeb]

aarch32/aarch32-cpu/src/lib.rs

Lines 34 to 35 in 025b50d

	#[cfg(any(test, doc, arm_architecture = "v8-r"))]
	pub mod generic_timer;

As mentioned here, these registers also exist in armv7a.

aarch32/aarch32-cpu/src/generic_timer/mod.rs

Line 6 in 025b50d

//! The Generic Timer existed in Armv7-A as well, but not in Armv7-R.

[jonathanpallant]

Yes, we should extend that cfg.