feat(rmm):set size of RsiHostCall.gprs[] to 31

This patch sets the size of gprs[] array in RsiHostCall
structure to 31, as per RMM Specification 1.0-eac1.

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: I8916191aa7c3aa83c64dda70e5a65be2c6b28fb6
diff --git a/lib/smc/include/smc-rsi.h b/lib/smc/include/smc-rsi.h
index 381a168..f64b1f0 100644
--- a/lib/smc/include/smc-rsi.h
+++ b/lib/smc/include/smc-rsi.h
@@ -146,7 +146,7 @@
  */
 #define SMC_RSI_IPA_STATE_GET		SMC64_RSI_FID(U(0x8))
 
-#define RSI_HOST_CALL_NR_GPRS		U(7)
+#define RSI_HOST_CALL_NR_GPRS		U(31)
 
 #ifndef __ASSEMBLER__
 struct rsi_host_call {
@@ -161,7 +161,7 @@
 #endif /* __ASSEMBLER__ */
 
 /*
- * arg0 == struct rsi_host_call addr
+ * arg0 == struct rsi_host_call address
  */
 #define SMC_RSI_HOST_CALL		SMC64_RSI_FID(U(0x9))