ARM: dts: OMAP2+: Replace underscores in sub-mailbox node names

stable inclusion
from stable-5.10.53
commit 28d2ae98154e470ab9bd0e36d556d02e8119b1ad
bugzilla: 175574 https://gitee.com/openeuler/kernel/issues/I4DTUX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=28d2ae98154e470ab9bd0e36d556d02e8119b1ad



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[ Upstream commit 9e7f5ee1 ]

A number of sub-mailbox node names in various OMAP2+ dts files are
currently using underscores. This is not adhering to the node name
convention, fix all of these to use hiphens.

These nodes are already using the prefix mbox, so they will be in
compliance with the sub-mailbox node name convention being added in
the OMAP Mailbox YAML binding as well.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>