Fix compile on powerpc64/powerpc64le w/ altivec

Correct the type of some vectors passed to vec_slo() or vec_sro(), which only
takes a char vector.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>

--- a/src/dvbcsa_bs_altivec.h	2016-11-28 14:33:34.410021500 +1100
+++ b/src/dvbcsa_bs_altivec.h	2016-11-28 14:34:25.442238715 +1100
@@ -64,7 +64,7 @@
 	}
 	case 0x29: {
 		dvbcsa_bs_word_t x = vec_splat_u8(10);
-		return (dvbcsa_bs_word_t)vec_add(vec_splat_u8(0x1),vec_rl(x,x));
+		return (dvbcsa_bs_word_t)vec_add((dvbcsa_bs_word_t)vec_splat_u8(0x1),vec_rl(x,x));
 	}
 	case 0x40: {
 		dvbcsa_bs_word_t x = vec_splat_u8(4);
@@ -99,10 +99,10 @@
 #define SHVAL_14 BS_VAL8(0e)
 #define SHVAL_7 BS_VAL8(07)
 
-#define BS_SHL(a, n)	({ dvbcsa_bs_word_t x = SHVAL_##n; vec_sll(vec_slo((a), x), x); })
-#define BS_SHR(a, n)	({ dvbcsa_bs_word_t x = SHVAL_##n; vec_srl(vec_sro((a), x), x); })
-#define BS_SHL8(a, n)	({ dvbcsa_bs_word_t x = vec_splat_u8(n*2); x = vec_add(x,x); x = vec_add(x,x); vec_slo((a), x); })
-#define BS_SHR8(a, n)	({ dvbcsa_bs_word_t x = vec_splat_u8(n*2); x = vec_add(x,x); x = vec_add(x,x); vec_sro((a), x); })
+#define BS_SHL(a, n)	({ vector unsigned char x = SHVAL_##n; vec_sll(vec_slo((a), x), x); })
+#define BS_SHR(a, n)	({ vector unsigned char x = SHVAL_##n; vec_srl(vec_sro((a), x), x); })
+#define BS_SHL8(a, n)	({ vector unsigned char x = vec_splat_u8(n*2); x = vec_add(x,x); x = vec_add(x,x); vec_slo((a), x); })
+#define BS_SHR8(a, n)	({ vector unsigned char x = vec_splat_u8(n*2); x = vec_add(x,x); x = vec_add(x,x); vec_sro((a), x); })
 
 #define BS_EXTRACT8(a, n) ((uint8_t*)&(a))[15 - (n)]