crypto: powerpc - convert to use crypto_simd_usable()

Replace all calls to in_interrupt() in the PowerPC crypto code with
!crypto_simd_usable().  This causes the crypto self-tests to test the
no-SIMD code paths when CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y.

The p8_ghash algorithm is currently failing and needs to be fixed, as it
produces the wrong digest when no-SIMD updates are mixed with SIMD ones.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/powerpc/crypto/crct10dif-vpmsum_glue.c

@@ -12,11 +12,13 @@
 
 #include <linux/crc-t10dif.h>
 #include <crypto/internal/hash.h>
+#include <crypto/internal/simd.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/cpufeature.h>
+#include <asm/simd.h>
 #include <asm/switch_to.h>
 
 #define VMX_ALIGN		16
@@ -32,7 +34,7 @@ static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len)
 	unsigned int tail;
 	u32 crc = crci;
 
-	if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || in_interrupt())
+	if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
 		return crc_t10dif_generic(crc, p, len);
 
 	if ((unsigned long)p & VMX_ALIGN_MASK) {