SUPPORT.MD: Fix matrix generation after 43c416d0d819 and 77c39a53cf5b

SUPPORT.MD: Fix matrix generation after 43c416d0d819 and 77c39a53cf5b

The script docs/support-matrix-generate throw the following error on the
latest staging.

MDCCSR_EL0
DBGDTR_EL0
DBGDTRTX_EL0
DBGDTRRX_EL0
DBGDSCRINT
DBGDTRTXINT
DBGDTRRXINT
^ cannot parse status codeblock line:
MDCCSR_EL0
 ? at docs/parse-support-md line 172, <F> chunk 1.

With the current indentation, it looks like the script thinks this is
a status code block.

Solve the issue by switching to a bullet list.

Fixes: 43c416d0d819 ("xen/arm: arm64: Add emulation of Debug Data Transfer Registers")
Fixes: 77c39a53cf5b ("xen/arm: arm32: Add emulation of Debug Data Transfer Registers")
Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>