ARCv3: add architecrute PAGE_KERNEL* defs instead of generic

Add architecture specific versions of PAGE_KERNEL_EXEC and
PAGE_KERNEL_RO definitions to provide correct set of PT flags.
Without these explicit definitions default PAGE_KERNEL is used.
After commit f32ebe7 ("ARC: Proper kernel mapping") PAGE_KERNEL
definitions doesn't contain flag to permit code execution from
page and it provides modules load issue.
This patch fixes modules load issue.

Fixes: f32ebe7 ("ARC: Proper kernel mapping")
Signed-off-by: Pavel Kozlov <pavel.kozlov@synopsys.com>

Author: pavelvkozlov

arch/arc/include/asm/pgtable-bits-arcv3.h

@@ -86,6 +86,10 @@
 #define PAGE_KERNEL_RW	__pgprot(_PAGE_KERNEL)
 #define PAGE_KERNEL_RWX	__pgprot(_PAGE_KERNEL & ~_PAGE_NOTEXEC_K)
 
+/* Use arcitecture specific PAGE_KERNEL_* instead of generic fallbacks */
+#define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL & ~_PAGE_NOTEXEC_K)
+#define PAGE_KERNEL_RO 		__pgprot(_PAGE_KERNEL | _PAGE_AP_READONLY)
+
 #define PAGE_KERNEL_BLK		__pgprot(_PAGE_KERNEL & ~_PAGE_LINK)
 #define PAGE_KERNEL_BLK_RW	__pgprot(_PAGE_KERNEL & ~_PAGE_LINK)
 #define PAGE_KERNEL_BLK_RWX	__pgprot(_PAGE_KERNEL & ~_PAGE_NOTEXEC_K & ~_PAGE_LINK)