libplatsupport: exynos ltimer drivers refactor

This commit refactors the timer implementation for
exynos to use the new driver framework APIs. Folds callbacks
and ownership of IRQ and memory maps into the device-handling
code itself.

exynos4_MCS: bug fix in platsupport

Clock frequencies were wrong for exy4 vs exy5.
Two bugs in the get_time code calculation
(one race condition and the calculation (ACLK_66 / 1000.0)
was flooring the constant to 0).

exynos: Fix timer irq handling

It was switched, so timer4 would handle timer0's irqs and vice versa.

exynos: initialise time_h in timer driver

Remove global variables in pwm

- put time_h into pwm struct
- remove prescale0 - it's not used

exynos: Remove pstimer from pwm

- delete empty files
- refactor pwm for ltimer use

exynos: add missing timer irqs, use in pwm_handle_interrupt

Fix whitespace

- remove trailing whitespace
- remove duplicate blank lines
- remove blank lines at end of file

Change 1 << * to BIT(*) in some cases

fix licenses

libplatsupport: Use stubtimer timeout method

Remove a bunch of duplicated code.

libplatsupport: Expand timer properties

Indicate the types of timeout supported in the properties.

libplatsupport: Use stubtimer timeout method

Remove a bunch of duplicated code.

libplatsupport: Expand timer properties

Indicate the types of timeout supported in the properties.