Revert "timers: Rename del_timer() to timer_delete()"

This reverts commit b086d1e8 which is
commit bb663f0f upstream.

It breaks the Android kernel abi by turning del_timer() into an
inline function, which breaks the abi.  Fix this by putting it back
as needed AND fix up the only use of this new function in
net/hsr/hsr_device.c which is what caused this commit to be backported
to 6.1.91 in the first place.

Bug: 161946584
Change-Id: I033a9b5d57acaffdfc1973f6f77bc4e92675b7e4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>