ARC: Add support for generic HS48 processor

For the HS48 processor, BR currently builds with -mcpu=hs4x_rel31 which
generates suboptimal code as it inhibits delay slot and back-back ST and so on.

Enable a new variant to build with -mcpu=hs4x for normal codegen.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[yann.morin.1998@free.fr:
  - simplify dependencies on MMU page size
  - wrap long lines
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

arch/Config.in.arc

@@ -39,9 +39,14 @@ config BR2_archs38_full
 
 config BR2_archs4x_rel31
 	bool "ARC HS48 rel 31"
+	help
+	   Build for HS48 release 3.1
+
+config BR2_archs4x
+	bool "ARC HS48"
 	help
 	   Latest release of HS48 processor
-	   - Dual- and quad multiply and MC oprations
+	   - Dual and Quad multiply and MAC operations
 	   - Double-precision FPU
 
 endchoice
@@ -49,7 +54,9 @@ endchoice
 # Choice of atomic instructions presence
 config BR2_ARC_ATOMIC_EXT
 	bool "Atomic extension (LLOCK/SCOND instructions)"
-	default y if BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
+	default y if BR2_arc770d
+	default y if BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full
+	default y if BR2_archs4x_rel31 || BR2_archs4x
 
 config BR2_ARCH
 	default "arc"	if BR2_arcle
@@ -70,10 +77,12 @@ config BR2_GCC_TARGET_CPU
 	default "hs38"	 if BR2_archs38_64mpy
 	default "hs38_linux"	 if BR2_archs38_full
 	default "hs4x_rel31"	 if BR2_archs4x_rel31
+	default "hs4x"	 if BR2_archs4x
 
 config BR2_READELF_ARCH_NAME
 	default "ARCompact"	if BR2_arc750d || BR2_arc770d
-	default "ARCv2"		if BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
+	default "ARCv2"		if BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full
+	default "ARCv2"		if BR2_archs4x_rel31 || BR2_archs4x
 
 choice
 	prompt "MMU Page Size"
@@ -93,7 +102,7 @@ choice
 
 config BR2_ARC_PAGE_SIZE_4K
 	bool "4KB"
-	depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
+	depends on !BR2_arc750d
 
 config BR2_ARC_PAGE_SIZE_8K
 	bool "8KB"
@@ -103,7 +112,7 @@ config BR2_ARC_PAGE_SIZE_8K
 
 config BR2_ARC_PAGE_SIZE_16K
 	bool "16KB"
-	depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
+	depends on !BR2_arc750d
 
 endchoice