Documentation: powerpc: Expand the DAWR acronym

Those not of us not drowning in POWER might not know what this means.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Documentation/powerpc/DAWR-POWER9.txt

 DAWR issues on POWER9
 ============================
 
-On POWER9 the DAWR can cause a checkstop if it points to cache
-inhibited (CI) memory. Currently Linux has no way to disinguish CI
-memory when configuring the DAWR, so (for now) the DAWR is disabled by
-this commit:
+On POWER9 the Data Address Watchpoint Register (DAWR) can cause a checkstop
+if it points to cache inhibited (CI) memory. Currently Linux has no way to
+disinguish CI memory when configuring the DAWR, so (for now) the DAWR is
+disabled by this commit:
 
     commit 9654153158d3e0684a1bdb76dbababdb7111d5a0
     Author: Michael Neuling <mikey@neuling.org>