staging: sm750fb: convert logging to device-based in sm750_hw.c

staging: sm750fb: convert logging to device-based in sm750_hw.c

Replace pr_err() calls with dev_err() using &pdev->dev or
&sm750_dev->pdev->dev to provide proper device context in log
messages. This makes it easier to identify which device generated
the message when multiple framebuffer devices are present.

Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
Link: https://patch.msgid.link/20260223204036.1780-3-iprintercanon@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>