spi: pl022: Don't touch unspecified bits in interrupt mask

PL022 Programmers model explicitely states "do not modify undefined register
bits". Correct the "all enable" interrupt mask so that it only enables defined
ones.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-pl022.c

@@ -285,7 +285,12 @@
  */
 #define DEFAULT_SSP_REG_IMSC  0x0UL
 #define DISABLE_ALL_INTERRUPTS DEFAULT_SSP_REG_IMSC
-#define ENABLE_ALL_INTERRUPTS (~DEFAULT_SSP_REG_IMSC)
+#define ENABLE_ALL_INTERRUPTS ( \
+	SSP_IMSC_MASK_RORIM | \
+	SSP_IMSC_MASK_RTIM | \
+	SSP_IMSC_MASK_RXIM | \
+	SSP_IMSC_MASK_TXIM \
+)
 
 #define CLEAR_ALL_INTERRUPTS  0x3