ARM: OMAP2+: DRA7: clockdomain: change l4per2_7xx_clkdm to SW_WKUP

Legacy IPs like PWMSS, present under l4per2_7xx_clkdm, cannot support
smart-idle when its clock domain is in HW_AUTO on DRA7 SoCs. Hence,
program clock domain to SW_WKUP.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: <stable@vger.kernel.org>