package/pixman: fix mips build

Disable Loongson MMI fast paths to fix the following mips build failure:

./loongson-mmintrin.h:407:2: error: impossible constraint in 'asm'
  407 |  asm("pinsrh_%3 %0, %1, %2\n\t"
      |  ^~~

Fixes:
 - http://autobuild.buildroot.org/results/75267aa5b5a631f091d4c8cb6ad9baeb5f72ee11
 - http://autobuild.buildroot.org/results/55b7431a50b85c24406131af1932d6f3f6853de6

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/pixman/pixman.mk

@@ -19,7 +19,9 @@ HOST_PIXMAN_DEPENDENCIES = host-pkgconf
 PIXMAN_AUTORECONF = YES
 
 # don't build gtk based demos
-PIXMAN_CONF_OPTS = --disable-gtk
+PIXMAN_CONF_OPTS = \
+	--disable-gtk \
+	--disable-loongson-mmi
 
 # The ARM SIMD code from pixman requires a recent enough ARM core, but
 # there is a runtime CPU check that makes sure it doesn't get used if