Remove DECLARE_GLOBAL_DATA_PTR from files where gd is not used, and
drop the unnecessary inclusion of asm/global_data.h.

Headers should be included directly by the files that need them,
rather than indirectly via global_data.h.

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> #STMicroelectronics boards and STM32MP1 ram test driver
Tested-by: Anshul Dalal <anshuld@ti.com> #TI boards
Acked-by: Yao Zi <me@ziyao.cc> #TH1520
Signed-off-by: Peng Fan <peng.fan@nxp.com>

This patch provides a driver for i.MX Messaging Unit (MU) using the
commom mailbox framework.

This is ported from Linux (v6.12.8) driver
drivers/mailbox/imx-mailbox.c. Its commit SHA is:
39d7d6177f0c ("mailbox: imx: use device name in interrupt name")

Signed-off-by: Viorel Suman <viorel.suman@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>