[PATCH] string: implement streq()

[Alexey Dobriyan <adobriyan@gmail.com>]

Most of the time strcmp() is being used, strings are checked for equality.
Add wrapper to relay such intent (it is shorter to type, too).

Use
	if (streq(s, "s")) {
	}
or
	if (!streq(s, "s")) {
	}

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 drivers/clk/socfpga/clk-gate-a10.c |    2 --
 drivers/clk/socfpga/clk.h          |    1 -
 include/linux/string.h             |    6 ++++++
 scripts/dtc/dtc.h                  |    6 +++++-
 4 files changed, 11 insertions(+), 4 deletions(-)

--- a/drivers/clk/socfpga/clk-gate-a10.c
+++ b/drivers/clk/socfpga/clk-gate-a10.c
@@ -11,8 +11,6 @@
 
 #include "clk.h"
 
-#define streq(a, b) (strcmp((a), (b)) == 0)
-
 #define to_socfpga_gate_clk(p) container_of(p, struct socfpga_gate_clk, hw.hw)
 
 /* SDMMC Group for System Manager defines */
--- a/drivers/clk/socfpga/clk.h
+++ b/drivers/clk/socfpga/clk.h
@@ -19,7 +19,6 @@
 
 #define SOCFPGA_MAX_PARENTS		5
 
-#define streq(a, b) (strcmp((a), (b)) == 0)
 #define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel) \
 	((((smplsel) & 0x7) << 3) | (((drvsel) & 0x7) << 0))
 
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -47,6 +47,12 @@ extern size_t strlcat(char *, const char *, __kernel_size_t);
 #ifndef __HAVE_ARCH_STRCMP
 extern int strcmp(const char *,const char *);
 #endif
+
+static inline bool streq(const char *a, const char *b)
+{
+	return strcmp(a, b) == 0;
+}
+
 #ifndef __HAVE_ARCH_STRNCMP
 extern int strncmp(const char *,const char *,__kernel_size_t);
 #endif
--- a/scripts/dtc/dtc.h
+++ b/scripts/dtc/dtc.h
@@ -88,7 +88,11 @@ static inline uint64_t dtb_ld64(const void *p)
 		| bp[7];
 }
 
-#define streq(a, b)	(strcmp((a), (b)) == 0)
+static inline bool streq(const char *a, const char *b)
+{
+	return strcmp(a, b) == 0;
+}
+
 #define strstarts(s, prefix)	(strncmp((s), (prefix), strlen(prefix)) == 0)
 #define strprefixeq(a, n, b)	(strlen(b) == (n) && (memcmp(a, b, n) == 0))
 static inline bool strends(const char *str, const char *suffix)