remoteproc: k3-dsp: Flush D cache after loading firmware

remoteproc: k3-dsp: Flush D cache after loading firmware

Memory region used by remote cores was set to non-cached region but
commit 7c9c6e192580 ("arm: mach-k3: Merge initial memory maps") makes
all memory region as cached, unified across K3 devices.

This causes inconsistency while booting remote cores on devices, due to
cache incoherency between remote core and boot code.

So to make this operation coherent, cache the address and len while
loading ELF program headers to memory and flush that region in the next
cycle of load.

Signed-off-by: Udit Kumar <u-kumar1@ti.com>
Signed-off-by: Beleswar Padhi <b-padhi@ti.com>