Revert "drm/xe: Force write completion of MI_STORE_DATA_IMM"

This reverts commit 1460bb1f.

In all places the MI_STORE_DATA_IMM are not followed by a read of
the same memory address in the same batch buffer and the posted writes
are flushed with PIPE_CONTROL or MI_FLUSH_DW in xe_ring_ops.c functions
so there is no need to set this register.

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Fixes: 1460bb1f ("drm/xe: Force write completion of MI_STORE_DATA_IMM")
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241227183230.101334-1-jose.souza@intel.com