ARM: 6826/1: Merge v6 and v7 DEBUG_LL DCC support

The inline assembly differences for v6 vs. v7 are purely
optimizations. On a v7 processor, an mrc with the pc sets the
condition codes to the 28-31 bits of the register being read. It
just so happens that the TX/RX full bits the DCC support code is
testing for are high enough in the register to be put into the
condition codes. On a v6 processor, this "feature" isn't
implemented and thus we have to do the usual read, mask, test
operations to check for TX/RX full. Thus, we can drop the v7
implementation and just use the v6 implementation for both.

Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>