add missing key to some yaml files

boards/uniboard2b/libraries/unb2b_board/unb2b_board.peripheral.yaml

@@ -121,4 +121,4 @@ peripherals:
         slave_description: " "
 
     peripheral_description: |
-        "
\ No newline at end of file
+        ""
\ No newline at end of file

libraries/base/diag/diag.peripheral.yaml

@@ -67,6 +67,7 @@ peripherals:
               address_offset: 0x1c
               field_description: |
                   "This REG specifies the higher(MSB) 32 bits [63:32] of the initialization BSN"
+        slave_description: ""
         
         # actual hdl name: ram_diag_bg
       - slave_name   : wave_data  
@@ -78,6 +79,7 @@ peripherals:
               number_of_fields: 2**g_buf_addr_w
               field_description  : |
                   "Contains the Waveform data for the data-streams to be send"
+        slave_description: ""
     peripheral_description: |
         "Block generator"
   

libraries/io/epcs/epcs.peripheral.yaml

@@ -76,6 +76,7 @@ peripherals:
               address_offset: 0x0
               number_of_fields: 1
               field_description: "  "
+        slave_description: " "
       
       - slave_name   : DPMM_DATA
         slave_type   : FIFO
@@ -86,6 +87,7 @@ peripherals:
               address_offset: 0x0
               number_of_fields: 1
               field_description: "  "
+        slave_description: " "
 
       # actual hdl name: mms_dp_fifo_from_mm
       - slave_name   : MMDP_CTRL
@@ -97,6 +99,7 @@ peripherals:
               address_offset: 0x0
               number_of_fields: 2
               field_description: "  "
+        slave_description: " "
       
       - slave_name   : MMDP_DATA
         slave_type   : FIFO
@@ -107,6 +110,7 @@ peripherals:
               address_offset: 0x0
               number_of_fields: 2
               field_description: "  "
+        slave_description: " "
     
     peripheral_description: |
         "wi  Bits     SE  R/W Name              Default  Description         |REG_EPCS|