Blackfin: BF51x/BF52x: fill out bfin_clear_PPI_STATUS()

All the arches define a helper macro to make things easy for driver code.
Reported-by: Frank Van Hooft <frank@frankvh.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/mach-bf518/include/mach/cdefBF51x_base.h

@@ -844,6 +844,7 @@
 #define bfin_write_PPI_CONTROL(val)		bfin_write16(PPI_CONTROL, val)
 #define bfin_read_PPI_STATUS()			bfin_read16(PPI_STATUS)
 #define bfin_write_PPI_STATUS(val)		bfin_write16(PPI_STATUS, val)
+#define bfin_clear_PPI_STATUS()			bfin_write_PPI_STATUS(0xFFFF)
 #define bfin_read_PPI_DELAY()			bfin_read16(PPI_DELAY)
 #define bfin_write_PPI_DELAY(val)		bfin_write16(PPI_DELAY, val)
 #define bfin_read_PPI_COUNT()			bfin_read16(PPI_COUNT)

arch/blackfin/mach-bf527/include/mach/cdefBF52x_base.h

@@ -844,6 +844,7 @@
 #define bfin_write_PPI_CONTROL(val)		bfin_write16(PPI_CONTROL, val)
 #define bfin_read_PPI_STATUS()			bfin_read16(PPI_STATUS)
 #define bfin_write_PPI_STATUS(val)		bfin_write16(PPI_STATUS, val)
+#define bfin_clear_PPI_STATUS()			bfin_write_PPI_STATUS(0xFFFF)
 #define bfin_read_PPI_DELAY()			bfin_read16(PPI_DELAY)
 #define bfin_write_PPI_DELAY(val)		bfin_write16(PPI_DELAY, val)
 #define bfin_read_PPI_COUNT()			bfin_read16(PPI_COUNT)