ARM11: use shared DSCR bit names

For the bits now defined in "arm_dpm.h", switch to the
shared DSCR_* symbol and remove the ARM11_DSCR_* version.

Define DSCR_INT_DIS and use it instead of the ARM11_DSCR_*
sibling symbol.  (Note:  for both ARM11 and Cortex-A8, this
should arguably be enabled by default when single stepping.)

Remove some other unused declarations in "arm11.h".

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/arm_dpm.h

@@ -141,6 +141,7 @@ void arm_dpm_report_wfar(struct arm_dpm *, uint32_t wfar);
  */
 #define DSCR_CORE_HALTED	(1 << 0)
 #define DSCR_CORE_RESTARTED	(1 << 1)
+#define DSCR_INT_DIS		(1 << 11)
 #define DSCR_ITR_EN		(1 << 13)
 #define DSCR_HALT_DBG_MODE	(1 << 14)
 #define DSCR_MON_DBG_MODE	(1 << 15)