drivers: scsi: Add 'erase' support

UFS devices uses the block and scsi frameworks. Enable UFS erase
support by adding erase support to SCSI.

Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
diff --git a/cmd/scsi.c b/cmd/scsi.c
index c286bdc..9f76134 100644
--- a/cmd/scsi.c
+++ b/cmd/scsi.c
@@ -60,7 +60,8 @@
 	"scsi read addr blk# cnt - read `cnt' blocks starting at block `blk#'\n"
 	"     to memory address `addr'\n"
 	"scsi write addr blk# cnt - write `cnt' blocks starting at block\n"
-	"     `blk#' from memory address `addr'"
+	"     `blk#' from memory address `addr'\n"
+	"scsi erase blk# cnt - erase `cnt' blocks starting at block `blk#'"
 );
 
 U_BOOT_CMD(