drm/msm/dpu: split irq_control into irq_enable and _disable

The single helper for both enable and disable cases is too complicated,
especially if we start adding more code to these helpers. Split it into
irq_enable and irq_disable cases.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/577526/
Link: https://lore.kernel.org/r/20240208-fd_remove_phys_ops_atomic_mode_set-v4-1-caf5dcd125c0@linaro.org