hwaccess: use __asm__ as it is done elsewhere

`asm()` doesn't work with musl libc, as it is specific to glibc. Thus,
use `__asm__` as it is done elsewhere to fix compilation under
non-glibc.

Change-Id: I834fa6e171d2b20e1a5faa5a2e8f54caf107171a
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/63487
Original-Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Original-Reviewed-by: Thomas Heijligen <src@posteo.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72340
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/hwaccess_physmap.c b/hwaccess_physmap.c
index 1088405..1f60179 100644
--- a/hwaccess_physmap.c
+++ b/hwaccess_physmap.c
@@ -383,18 +383,18 @@
 #if defined(__powerpc) || defined(__powerpc__) || defined(__powerpc64__) || defined(__POWERPC__) || \
       defined(__ppc__) || defined(__ppc64__) || defined(_M_PPC) || defined(_ARCH_PPC) || \
       defined(_ARCH_PPC64) || defined(__ppc)
-	asm("eieio" : : : "memory");
+	__asm__("eieio" : : : "memory");
 #elif (__sparc__) || defined (__sparc)
 #if defined(__sparc_v9__) || defined(__sparcv9)
 	/* Sparc V9 CPUs support three different memory orderings that range from x86-like TSO to PowerPC-like
 	 * RMO. The modes can be switched at runtime thus to make sure we maintain the right order of access we
 	 * use the strongest hardware memory barriers that exist on Sparc V9. */
-	asm volatile ("membar #Sync" ::: "memory");
+	__asm__ volatile ("membar #Sync" ::: "memory");
 #elif defined(__sparc_v8__) || defined(__sparcv8)
 	/* On SPARC V8 there is no RMO just PSO and that does not apply to I/O accesses... but if V8 code is run
 	 * on V9 CPUs it might apply... or not... we issue a write barrier anyway. That's the most suitable
 	 * operation in the V8 instruction set anyway. If you know better then please tell us. */
-	asm volatile ("stbar");
+	__asm__ volatile ("stbar");
 #else
 	#error Unknown and/or unsupported SPARC instruction set version detected.
 #endif