LoongArch: Remove posix_types.h include from sigcontext.h

Nothing in sigcontext.h seems to require anything from
linux/posix_types.h.  This include seems a MIPS relic originated from
an error in Linux 2.6.11-rc2 (in 2005).

The unneeded include was found debugging some vDSO self test build
failure (it's not the root cause though).

Link: https://lore.kernel.org/linux-mips/[email protected]/
Link: https://lore.kernel.org/loongarch/[email protected]/
Signed-off-by: Xi Ruoyao <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>

Author: xry111

arch/loongarch/include/uapi/asm/sigcontext.h

@@ -9,7 +9,6 @@
 #define _UAPI_ASM_SIGCONTEXT_H
 
 #include <linux/types.h>
-#include <linux/posix_types.h>
 
 /* FP context was used */
 #define SC_USED_FP		(1 << 0)