SUPPORT.MD: Fix matrix generation after 43c416d0d8 and 77c39a53cf

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: 43c416d0d8 ("xen/arm: arm64: Add emulation of Debug Data Transfer Registers")
Fixes: 77c39a53cf ("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>

SUPPORT.md

@@ -111,13 +111,13 @@ that would normally trigger a fault injection.
 
 Only the following system registers are security supported:
 
-    MDCCSR_EL0
-    DBGDTR_EL0
-    DBGDTRTX_EL0
-    DBGDTRRX_EL0
-    DBGDSCRINT
-    DBGDTRTXINT
-    DBGDTRRXINT
+  * MDCCSR_EL0
+  * DBGDTR_EL0
+  * DBGDTRTX_EL0
+  * DBGDTRRX_EL0
+  * DBGDSCRINT
+  * DBGDTRTXINT
+  * DBGDTRRXINT
 
 ### ARM Scalable Vector Extension (SVE/SVE2)